Class 12 Chemistry Chapter 16 Chemistry In Everyday Life Notes and Important Question

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Introduction

  • Chemistry is essentially the study of materials and the development of new materials for the betterment of humanity.
  • In our daily life we use so many substances like toothpaste, soaps, sugar etc. which are made up of chemicals compounds.
  • In this lesson we will try to learn the uses and applications of chemistry in our day-to day life.
  • For Example: – The basic common salt, baking soda, fruits; vegetables all are made up of carbon compounds.
  • There are 3 important areas  where we use chemistry in our life is:-
    • Medicines
    • Food materials
    • Cleaning agents

Importance of Chemistry in our daily life: Medicines

  • A drug is a chemical agent, which affects human metabolism and provides cure from ailment.
  • Or Drugs are chemicals which interact with macromolecular targets and produce a biological response.
  • Drugs will interact with macromolecules targets (where these targets are chemical compounds like proteins, lipids etc.) in order to maintain balance in the body.
  • When the biological response is therapeutic and useful, these chemicals are called medicines and are used in diagnosis, prevention and treatment of diseases.
  • Medicines are sub classification of the drugs. They produce good response and they are useful in order to diagnosis, prevention and treatment of diseases.
  • If taken in doses higher than those recommended, most of the drugs used as medicines are potential poisons.
  • Use of chemicals for treatment and cure of disease is called chemotherapy.
    • The treatment of disease by chemical compound which destroy the microorganisms without attacking the tissue of the human body is known as chemotherapy.
    • The compounds used are called chemotherapeutic agents.

Classification of drugs

  • On the basis of pharmacological effect
  • On the basis of drug action
  • On the basis of chemical structure
  • On the basis of molecular targets

Pharmacological effect

  • This classification is based on pharmacological effect of the drugs.
  • It is useful for doctors because it provides them the whole range of drugs available for the treatment of a particular type of problem.
    • For example, analgesics have pain killing effect; antiseptics kill or arrest the growth of microorganisms.

 Drug Action

  • It is based on the action of a drug on a particular biochemical process.
  • For example, all antihistamines inhibit the action of the compound, histamine which causes inflammation in the body. There are various ways in which action of histamines can be blocked.
  • Aspirin controls the synthesis of chemicals known as prostaglandins

Chemical Structure

  • It is based on the chemical structure of the drug.
  • Drugs classified in this way share common structural features and often have similar pharmacological activity.
  • For example, sulphonamides have common structural feature, given below.

Molecular targets

  • Drugs usually interact with biomolecules such as carbohydrates, lipids, proteins and nucleic acids.
  • These are called target molecules or drug targets.
  • Drugs possessing some common structural features may have the same mechanism of action on targets.

Drug- Target Interaction as Enzymes

  • Macromolecules of biological origin perform various functions in the body.
    •  For example, proteins which perform the role of biological catalysts in the body are called enzymes.
    • They are crucial to communication system in the body are called receptors.
  • Carrier proteins carry polar molecules across the cell membrane.
  • Nucleic acids have coded genetic information for the cell. Lipids and carbohydrates are structural parts of the cell membrane.
  • Catalytic Action of Enzymes
  • In order to carry catalytic activity enzymes perform 2 major functions:
  1. The first function of an enzyme is to hold the substrate for a chemical reaction. Active sites of enzymes hold the substrate molecule in a suitable position, so that it can be attacked by the reagent effectively.

Substrates bind to the active site of the enzyme through a variety of interactions such as ionic bonding, hydrogen bonding, van der Waals interaction or dipole-dipole interaction.

  1. The second function of an enzyme is to provide functional groups that will attack the substrate and carry out chemical reaction.
  • Drug-Enzyme Interaction
  • These drugs can block the binding site of the enzyme and prevent the binding of substrate, or can inhibit the catalytic activity of the enzyme. Such drugs are called enzyme inhibitors.
  • Drugs inhibit the attachment of substrate on active site of enzymes in two different ways;
  • Drugs compete with the natural substrate for their attachment on the active sites of enzymes. Such drugs are called competitive inhibitors.
  • Some drugs do not bind to the enzyme’s active site. These bind to a different site of enzyme which is called allosteric site. This binding of inhibitor at allosteric site changes the shape of the active site in such a way that substrate cannot recognise it.
  • Note:-
  • If the bond formed between an enzyme and an inhibitor is a strong covalent bond and cannot be broken easily, then the enzyme is blocked permanently.
  • The body then degrades the enzyme-inhibitor complex and synthesises the new enzyme.

Drug- Target Interaction as Receptors

  • Receptors are proteins that are crucial to body’s communication process.
  • Receptor proteins are embedded in the cell membrane in such a way that their small part possessing active site projects out of the surface of the membrane and opens on the outside region of the cell membrane.
  • In the body, message between two neurons and that between neurons of muscles is communicated through certain chemicals.
  • These chemicals are known as chemical messengers and are received at the binding sites of receptor proteins.
  • To accommodate a messenger, shape of the receptor site changes, as a result transfer of message happens into the cell.
  • Thus, chemical messenger gives message to the cell without entering the cell.
  • Note:-
  • There are a large number of different receptors in the body that interact with different chemical messengers.
  • These receptors show selectivity for one chemical messenger over the other because their binding sites have different shape, structure and amino acid composition.

Antagonists

  • Drugs that bind to the receptor site and inhibit its natural function are called antagonists.
  • These are useful when blocking of message is required.
  • There are other types of drugs that mimic the natural messenger by switching on the receptor, these are called agonists. These are useful when there is lack of natural chemical messenger.

Therapeutic Action of Different Classes of Drugs

Antacids

  • The chemical substances which neutralises the excess acid in gastric juice and raise pH to an appropriate level in stomach are called antacids.
  • For example: – Baking soda, mixture of Al and Mg hydroxide are commonly used antacids.
  • Generally liquids antacids are more effective than tablets because of more of surface area available for interaction and neutralisation acids.
  • Milk is a weak antacid.
  • By using excess hydrogen carbonate stomach will become more of alkaline and as a result more of acid production happens.
  • So Metal hydroxides are used instead of them which are insoluble and don’t increase the pH value also.
  • But they will only treat the symptoms not the cause.
  • A major breakthrough in the treatment of hyperacidity happened by the discovery of chemical known as histamine which stimulates the secretion of pepsin and hydrochloric acid in the stomach.
  • The drug cimetidine (Tegamet) was designed to prevent the interaction of histamine with the receptors present in the stomach wall.
  • This resulted in release of lesser amount of acid.
  • The importance of the drug was so much that it remained the largest selling drug in the world until another drug, ranitidine (Zantac), was discovered.

Antihistamines

  • Histamine is a potent vasodilator.
  • It has various functions. It contracts the smooth muscles in the bronchi and gut and relaxes other muscles, such as those in the walls of fine blood vessels.
  • Histamine is also responsible for the nasal congestion associated with common cold and allergic response to pollen.
  • Synthetic drugs, brompheniramine (Dimetapp) and terfenadine (Seldane) act as antihistamines.
  • They interfere with the natural action of histamine by competing with histamine for binding sites of receptor where histamine exerts its effect.
  • The antihistamines don’t affect the secretion of acid in the stomach because antiallegric and antacid drugs work on different receptors.

Neurologically Active Drugs

  • Tranquilizers and analgesics are neurologically active drugs. These affect the message transfer mechanism from nerve to receptor.
  • Tranquilizers
  • Tranquilizers are a class of chemical compounds used for the treatment of stress, and mild or even severe mental diseases.
  • These relieve anxiety, stress, irritability or excitement by inducing a sense of well-being. They form an essential component of sleeping pills.
  • There are various types of tranquilizers.
  • They function by different mechanisms.
  • For example, noradrenaline is one of the neurotransmitters that play a role in mood changes.
  • If the level of noradrenaline is low for some reason, then the signal-sending activity becomes low, and the person suffers from depression.
  • In such situations, antidepressant drugs are required
  • These drugs inhibit the enzymes which catalyse the degradation of noradrenaline.
  • If the enzyme is inhibited, this important neurotransmitter is slowly metabolised and can activate its receptor for longer periods of time, thus counteracting the effect of depression.
  • Iproniazid and phenelzine are two such drugs.
  • Some tranquilizers namely, chlordiazepoxide and meprobamate, are relatively mild tranquilizers suitable for relieving tension.
  • Equanil is used in controlling depression and hypertension.
  • Some important class of tranquilizers are as :
    • Derivatives of barbituric acid viz., veronal, amytal, nembutal, luminal and seconal.
    • These derivatives are called barbiturates. Barbiturates are hypnotic, i.e., sleep producing agents. Some other substances used as tranquilizers are valium and serotonin.
  • Analgesics
  • Analgesics reduce or finish the pain without causing impairment of consciousness, mental confusion, incoordination or paralysis or some other disturbances of nervous system.
  • These are classified as follows:

(i) Non-narcotic (non-addictive) analgesics

(ii) Narcotic drugs

  • Non-narcotic (non-addictive) analgesics
  • Aspirin and paracetamol belong to the class of non-narcotic analgesics.
  • Aspirin is the most common example. It inhibits the synthesis of chemicals known as prostaglandins which stimulate inflammation in the tissue and cause pain.
  • These drugs are effective in relieving skeletal pain such as that due to arthritis. These drugs have many other effects such as reducing fever (antipyretic). and preventing platelet coagulation.
  • They prevent platelet coagulation because of this anti-blood clotting action; aspirin finds use in prevention of heart attacks.
  • Aspirin is toxic for liver and sometimes causes bleeding from stomach. So naproxen, ibuprofen, paracetamol are widely used analgesics.
  • Narcotic Analgesics
  • Morphine and many of its homologues, when administered in medicinal doses, relieve pain and produce sleep.
  • In poisonous doses, these produce stupor, coma, convulsions and ultimately death.
  • Morphine narcotics are sometimes referred to as opiates, since they are obtained from the opium poppy.
  • These analgesics are chiefly used for the relief of postoperative pain, cardiac pain and pains of terminal cancer, and in child birth.

Antimicrobials

  • Diseases in human beings and animals may be caused by a variety of microorganisms such as bacteria, virus, fungi and other pathogens.
  • An antimicrobial tends to destroy/prevent development or inhibit the pathogenic action of microbes such as bacteria (antibacterial drugs), fungi (antifungal agents), virus (antiviral agents), or other parasites (antiparasitic drugs) selectively.
  • Antibiotics, antiseptics and disinfectants are antimicrobial drugs.

Antibiotics

  • Antibiotics are used as drugs to treat infections because of their low toxicity for humans and animals.
  • An antibiotic is a substance produced wholly or partly by chemical synthesis, which in low concentrations inhibits the growth or destroys microorganisms by intervening in their metabolic processes.
  • In order to find chemicals this will affect the invading bacteria and not the host.
  • Paul Ehrlich, a German bacteriologist, conceived this idea. He investigated arsenic based structures in order to produce less toxic substances for the treatment of syphilis.
  • He developed the medicine, arsphenamine, known as salvarsan.
  • Although salvarsan is toxic to human beings, its effect on the bacteria, spirochete, which causes syphilis, is much greater than on human beings.
  • He noted that there is similarity in structures of salvarsan and azodyes. The –As = As– linkage present in arsphenamine resembles the –N = N – linkage present in azodyes in the sense that arsenic atom is present in place of nitrogen.
  • In 1932, he succeeded in preparing the first effective antibacterial agent, prontosil, which resembles in structure to the compound, salvarsan. Soon it was discovered that in the body prontosil is converted to a compound called sulphanilamide, which is the real active compound. Thus the sulpha drugs were discovered.
  • A large range of sulphonamide analogues was synthesised. One of the most effective is sulphapyridine.
  • Despite the success of sulphonamides, the real revolution in antibacterial therapy began with the discovery of Alexander Fleming in 1929, of the antibacterial properties of a Penicillium fungus.
  • Antibiotics have either cidal (killing) effect or a static (inhibitory) effect on microbes.
  • A few examples of the two types of antibiotics are as follows:

Bactericidal                      Bacteriostatic

Penicillin                           Erythromycin

Aminoglycosides             Tetracycline

Ofloxacin                           Chloramphenicol

  • Antibiotics which kill or inhibit a wide range of Gram-positive and Gram-negative bacteria are said to be broad spectrum antibiotics.
  • Those are effective mainly against Gram-positive or Gram-negative bacteria are narrow spectrum antibiotics.
  • If effective against a single organism or disease, they are referred to as limited spectrum antibiotics.
  • Penicillin G has a narrow spectrum. Ampicillin and Amoxicillin are synthetic modifications of penicillin’s. These have broad spectrum.
  • It is absolutely essential to test the patients for sensitivity (allergy) to penicillin before it is administered.
  • In India, penicillin is manufactured at the Hindustan Antibiotics in Pimpri and in private sector industry.

Chloramphenicol

  • Chloramphenicol, isolated in 1947, is a broad spectrum antibiotic.
  • It is rapidly absorbed from the gastrointestinal tract and hence can be given orally in case of typhoid, dysentery, and acute fever, certain form of urinary infections, meningitis and pneumonia.
  • Vancomycin and ofloxacin are the other important broad spectrum antibiotics.
  • The antibiotic dysidazirine is supposed to be toxic towards certain strains of cancer cells.

Antiseptics & disinfectants

  • Antiseptics are applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces.
  • Examples are furacine, soframicine, etc. These are not ingested like antibiotics.
  • Commonly used antiseptic, Dettol is a mixture of chloroxylenol and terpineol. 
  • Bithionol (the compound is also called bithionol) is added to soaps to impart antiseptic properties.
  • Iodine is a powerful antiseptic. Its 2-3 per cent solution in alcohol water mixture is known as tincture of iodine.
  • It is applied on wounds.
  • Iodoform (CHI3) is also used as an antiseptic for wounds.
  • Boric acid in dilute aqueous solution is weak antiseptic for eyes.

Disinfectants

  • They are applied to inanimate objects such as floors, drainage system, instruments, etc. Same substances can act as an antiseptic as well as disinfectant by varying the concentration.
  • For example, 0.2 per cent solution of phenol is an antiseptic while its one percent solution is disinfectant.
  • Chlorine in the concentration of 0.2 to 0.4 ppm in aqueous solution and sulphur dioxide in very low concentrations, are disinfectants.

Antifertility Drugs

  • These are the chemical substances which are used to control pregnancy.
  • They are also called as oral contraceptives.
  • Birth control pills essentially contain a mixture of synthetic estrogen and progesterone derivatives. Both of these compounds are hormones.
  • It is known that progesterone suppresses ovulation.
  • Synthetic progesterone derivatives are more potent than progesterone.
  • Norethindrone is an example of synthetic progesterone derivative most widely used as antifertility drug. The estrogen derivative which is used in combination with progesterone derivative is ethynylestradiol (novestrol).

Chemicals in Food

  • Chemicals are added to the food for the following reasons:-
  1. Their preservation
  2. Enhancing their appeal
  3. Adding nutritive value in them.
  • Main categories of food additives are as follows:-
  1. Food colours
  1. Flavours and sweeteners

Sucrose (Natural sugar)

  1. Fat emulsifiers and stabilising agents
  2. Flour improvers – antistaling agents and bleaches
  3. Antioxidants
    1. Antioxidants prevent damage to the cells, cell proteins and lipids. They neutralize the free radicals which causes aging and degeneration of body.
    2. For example: – Vitamin E and Vitamin C etc. They are electron rich substances so they can denote electrons to free radicals which are causing age degeneration.
    3. They stabilize the age causing radicals.
  4. Preservatives
  5. Nutritional supplements such as minerals, vitamins and amino acids.

Artificial Sweetening Agents

  • Sucrose and fructose are the most widely used natural sweeteners.
  • But their intake increases calories in the diet and excess of them can cause tooth decay.
  • Ortho-sulphobenzimide, also called saccharin, is the first popular artificial sweetening agent. It is about 550 times as sweet as cane sugar. It appears to be entirely inert and harmless when taken.
  • Its use is of great value to diabetic persons and people who need to control intake of calories.

Aspartame

  • Aspartame is the most successful and widely used artificial sweetener. It is roughly 100 times as sweet as cane sugar.
  • It is methyl ester of dipeptide formed from aspartic acid and phenylalanine.
  • Use of aspartame is limited to cold foods and soft drinks because it is unstable at cooking temperature.
  • Sucralose is trichloro derivative of sucrose. Its appearance and taste are like sugar. It is stable at cooking temperature. It does not provide calories.

Food Preservatives

  • Food preservatives prevent spoilage of food due to microbial growth. The most commonly used preservatives include table salt, sugar, vegetable oils and sodium benzoate, C6H5COONa.
  • Sodium benzoate is used in limited quantities and is metabolised in the body. Salts of sorbic acid and propanoic acid are also used as preservatives.
  • There are 3 categories of food preservatives:-
    • Anti-microbial
      • It inhibits the growth of bacteria.
    • Anti-oxidant
      • They prevent damage to the cells, cell proteins and lipids. They neutralize the free radicals which causes aging and degeneration of body.
      • For Example: – BHT(butylated hydroxytoluene) and BRA(Butylated hydroxyanisole).
    • Anti-ripening
      • It will remove the oxygen from the substance. It is used to preserve fruits and vegetables.

Cleansing Agents

  • The word detergent means “cleansing agent”. Detergent is derived from Latin word “detergere” means “to wipe off”.
  • Cleansing agents are the substances which remove dirt and have cleansing action in water.
  • Detergents can be classified  into 2 types”
    • Soapy detergents or soaps.
    • Synthetic detergents

Soaps

  • Soaps are sodium or potassium salts of long chain fatty acids (containing 15-18 carbon atoms), e.g., stearic, oleic and palmitic acids.
  • Sodium salts of fatty acids are known as hard soaps and potassium salts of any fatty acids are known as soft soaps.

Preparation of Soap

  • Soaps containing sodium salts are formed by heating fat (i.e., glyceryl ester of fatty acid) with aqueous sodium hydroxide solution. This reaction is known as saponification.
  • In saponification esters of fatty acids are hydrolysed and the soap is obtained remains in colloidal form.
  • It is then precipitated from the solution by adding sodium chloride.
  • The solution left after removing the soap contains glycerol, which can be recovered by fractional distillation.
  • Only sodium and potassium soaps are soluble in water and are used for cleaning purposes.
  • As compared to sodium, potassium soaps are soft to the skin. These can be prepared by using potassium hydroxide solution in place of sodium hydroxide.

Types of Soaps

  • By using different types of raw materials different kinds of soaps are made.
  1. Toilet Soaps:-
    1. They are prepared by using better grades of fats and oils and care is taken to remove excess alkali.
    2.  Colour and perfumes are added to make these more attractive.
  2. Floating Soaps:-
    1. Soaps that float in water are made by beating tiny air bubbles before their hardening.
  3. Transparent Soaps:-
    1. They are prepared by dissolving the soap in ethanol and then evaporating the excess solvent.
  4. Medicated Soaps:-
    1. In this type of soaps substances of medicinal value are added.
  5. Shaving Soaps:-
    1. Shaving soaps contain glycerol to prevent rapid drying. A gum called, rosin is added while making them. It forms sodium rosinate which lathers well.
  6. Laundry Soaps:-
    1. They contain fillers like sodium rosinate, sodium silicate, borax and sodium carbonate.
  7. Soap Chips:-
    1. Soap chips are made by running a thin sheet of melted soap onto a cool cylinder and scraping off the soaps in small broken pieces.
  8. Soap Granules:-
    1. They are dried miniature soap bubbles.
  9. Soap powders and scouring:-
    1. Soaps contain some soap, a scouring agent (abrasive) such as powdered pumice or finely divided sand, and builders like sodium carbonate and trisodium phosphate.

Why Soaps don’t work in hard water

  • Hard water contains calcium and magnesium ions. These ions form insoluble calcium and magnesium soaps respectively when sodium or potassium soaps are dissolved in hard water.

C17H35COONa + CaCl2 à 2NaCl + (C17H35COO) Ca

Soap                                                  Insoluble calcium stearate (Soap)

  • These insoluble soaps separate as scum in water and are useless as cleansing agent. In fact these are hindrance to good washing, because the precipitate adheres onto the fibre of the cloth as gummy mass.
  • Soaps cannot be used in acidic solutions since acids precipitate the insoluble free fatty acids which stick to the fabrics and thus reduce the ability of the soaps to remove oil and grease from fabrics.

RCOONa + H+ à RCOOH + Na+

Soap                     Free fatty

                        acid precipitate out

  •  Hair washed with hard water looks dull because of this sticky precipitate. Dye does not absorb evenly on cloth washed with soap using hard water, because of this gummy mass.

Synthetic Detergents

  • Synthetic detergents are cleansing agents which have all the properties of soaps, but which actually do not contain any soap.
  • These can be used both in soft and hard water as they give foam even in hard water. Because calcium and magnesium salts are also detergents like their sodium salts are also soluble in water.
  • Some of the detergents give foam even in ice cold water.
  • Straight chain alkyl group contains detergents which are biodegradable whereas branched alkyl group containing detergents are non-biodegradable.
  • Synthetic detergents are mainly classified into three categories:
  • (i) Anionic detergents (ii) Cationic detergents and (iii) Non-ionic detergents
  • Anionic detergents:-
    1. Anionic detergents are sodium salts of sulphonated long chain alcohols or hydrocarbons.
    2. Alkyl hydrogen sulphates formed by treating long chain alcohols with concentrated sulphuric acid are neutralised with alkali to form anionic detergents. Similarly alkyl benzene sulphonates are obtained by neutralising alkyl benzene sulphonic acids with alkali.
    3. In anionic detergents, the anionic part of the molecule is involved in the cleansing action.
      • Sodium salts of alkylbenzenesulphonates are an important class of anionic detergents.
        • They are mostly used for household work. Anionic detergents are also used in toothpastes.
  • Cationic Detergents:
    1. They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions.
    2. Cationic part possesses a long hydrocarbon chain and a positive charge on nitrogen atom.
    3. Hence, these are called cationic detergents. Cetyltrimethylammonium bromide is a popular cationic detergent and is used in hair conditioners.
    4. Cationic detergents have germicidal properties and are expensive, therefore, these are of limited use.
  • Non-ionic Detergents:
    1. They do not contain any ion in their constitution.
    2. One such detergent is formed when stearic acid reacts with polyethylene glycol.
    3. Liquid dishwashing detergents are non-ionic type. Mechanism of cleansing action of this type of detergents is the same as that of soaps.
    4. These also remove grease and oil by micelle formation. Main problem that appears in the use of detergents is that if their hydrocarbon chain is highly branched, then bacteria cannot degrade this easily.
  •  
    1. These days the branching of the hydrocarbon chain is controlled and kept to the minimum. Unbranched chains can be biodegraded more easily and hence pollution is prevented.

Advantages of Synthetic detergents over Soaps

  1. They can be used with hard water which soap cannot do.
  2. They can be used in acidic medium unlike soaps.
  3. They are more soluble in water so form better latter than soaps.
  4. They have stronger cleaning action than soaps.
Chapter-16-Chemistry-In-Everyday-Life

NCERT Solutions For Class 12 Chemistry Chapter 16 Chemistry in Everyday Life

NCERT INTEXT QUESTIONS

16.1. Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take its doses without consultation with the doctor. Why?
Ans: Most of drugs taken in doses higher than recommended may produce harmful effects and act as poison and cause even death. Therefore, a doctor must always be consulted before taking the drug.

16.2. “Ranitidine is an antacid” With reference to which classification, has this statement been given?
Ans: Ranitidine is labelled as antacid since it is quite effective in neutralising the excess of acidity in the stomach. It is sold in the market under the trade name Zintac.

16.3. Why do we require artificial sweetening agents?
Ans: To reduce calorie intake and to protect teeth from decaying, we need artificial sweeteners.

16.4. Write the chemical equation for preparing sodium soap from glyceryl oleate and glyceryl palmitate. Structures of these compounds are given below:
(i) (C15H31COO)3C3H5-Glyceryl palmitate
(ii) (C17H32COO)3C3H5-Glyceryl oleate
Ans:

16.5. Following type of non-ionic detergents are present in liquid detergents, emulsifying agents and wetting agents. Label the hydrophilic and hydrophobic part in the molecule. Identify the functional group (s) present in the molecule.

Functional groups present in the detergent molecule are:
(i)ether
(ii)1°alcoholic group

NCERT EXRECISES

16.1. Why do we need to classify drugs in different ways?
Ans: Drugs are classified in following different ways:
(a) Based on pharmacological effect.
(b) Based on action on a particular biochemical process.
(c) Based on chemical structure.
(d) Based on molecular targets.
Each classification has its own usefulness.
(а) Classification based on pharmacological effect is useful for doctors because it provides them the whole range of drugs available for the treatment of a particular disease.
(b) Classification based on action on a particular biochemical proc*ess is useful for choosing the correct compound for designing the synthesis of a desired drug.
(c) Classification based on chemical structure helps us to design the synthesis of a number of structurally similar compounds having different substituents and then choosing the drug having least toxicity.
(d) Classification on the basis of molecular targets is useful for medical chemists so that they can design a drug which is most effective for a particular receptor site.

16.2. Explain the following as used in medicinal chemistry
(a) Lead compounds
(b) Target molecules or drug targets.

Ans:
(a) Lead compounds are the compounds which are effective in different drugs. They have specific chemical formulas and may be extracted either from natural sources (plants and animals) or may be synthesised in the laboratory.

(b) Target molecules or drug targets. An enzyme (E) functions by combining with the reactant (called substrate) denoted as ‘S’ to form an activated complex known as enzyme-substrate complex (E-S). The complex dissociates to form product and releases the enzyme for carrying out further activity.

16.3. Name the macro molecules that are chosen as drug targets.
Ans: Proteins, carbohydrates, lipids and nucleic acids are chosen as drug targets.

16.4. Why the medicines should not be taken without consulting doctors?
Ans: No doubt medicines are panacea for most of the body ailments. But their wrong choice and overdose can cause havoc and may even prove to be fatal. Therefore, it is of utmost importance that the medicines should not be given without consulting doctors.

16.5. Define the term chemotherapy.
Ans: It is the branch of chemistry that deals with the treatment of diseases by using chemicals as medicines.

16.6. Which forces are involved in holding the drugs to the active site of enzymes?
Ans: The following forces are involved in holding the drugs to the active site of enzymes:
(a) Hydrogen bonding
(b) Ionic bonding
(c) Dipole-dipole interactions
(d) van der Waals interactions

16.7. Antacids and antiallergic drugs interfere with the function of histamines but do not interfere with the function of each other. Explain.
Ans: They donot interfere with the functioning of each other because they work on different receptors in the body.Histamine stimulates the secretion of pepsin and hydrochloric acid in the stomach. The drug cimetidine (antacid) was designed to prevent the interaction of histamine with the receptors present in the stomach wall. This resulted in release of lesser amount of acid. Antacid and antiallergic drugs work on different receptors.

16.8. Low level of noradrenaline is the cause of depression. What type of drugs are needed to cure this problem? Name two drugs.
Ans: In case of low level of neurotransmitter, . noradrenaline, tranquilizer (antidepressant) drugs are required because low levels of noradrenaline leads to depression. These drugs inhibit the enzymes which catalyse the degradation of noradrenaline. If the enzyme is inhibited, noradrenaline is slowly metabolized and can activate its receptor for longer periods of time thereby reducing depression. Two important drugs are iproniazid and phenylzine.

16.9. What is meant by the term broad spectrum antibiotics? Explain.
Ans: Broad spectrum antibiotics are effective against several different types or wide range of harmful bacteria. For example, tetracycline, chloramphenicol and of loxacin. Chloramphenicol can be used in case of typhoid, dysentry, acute fever, urinary infections, meningitis and pneumonia.

16.10. How do antiseptics differ from disinfectants ? Give one example of each.
Ans: Many times, the same substance can act as an antiseptic as well as disinfectant by changing the concentration of the solution used. For example, a 0.2 per cent solution of phenol acts as an antiseptic and its 1 percent solution is a disinfectant. Chlorine is used in India for making water fit for drinking at a concentration of 0.2 to 0.4 ppm (parts per million). Low concentration of sulphur dioxide is used for sterilizing squashes for preservation. A few points of distinction between antiseptics and disinfectants are listed.

AntisepticsDisinfectants
1. Can kill or prevent the growth of micro-organisms.1.Can kill micro-organisms.
2. Do not harm the living tissues. Therefore, these can be applied to the skin.2. Toxic to the living tissues. Therefore, these cannot be applied to the skin.
3. These are used for the dressing of wounds, ulcers and in the treatment of diseased skin.3. These are used for disinfecting floors, toilets, drains, instruments etc.

16.11. Why are cimetidine and ranitidine better antacids than sodium hydrogencarbonate or magnesium or aluminium hydroxide?
Ans: If excess of NaHCO3 or Mg(OH)2 or Al(OH)3 is used, it makes the stomach alkaline and thus triggers the release of even more HCl which may cause ulcer in the stomach. In contrast, cimetidine and ranitidine prevent the interaction of histamine with the receptor cells in the stomach wall and thus release of HCl will be less as histamine stimulates the secretion of acid.

16.12. Name a substance which can be used as an antiseptic as well as disinfectant.
Ans: 0.2% solution of phenol acts as antiseptic while 1% solution acts as a disinfectant.

16.13. What are the main constituents of dettol?
Ans: Chloroxylenol .and α-terpineol in a suitable solvent.

16.14. What is tincture of iodine? What is its use?
Ans: 2-3% solution of iodine in alcohol and water is called tincture of iodine. It is a powerful antiseptic. It is applied on wounds.

16.15. What are food preservatives?
Ans: Preservation has a major role in the food products. Chemically preserved squashes and crushes can be kept for a fairly long time even after opening the seal of bottle.
A preservative may be defined as the substance which is capable of inhibiting or arresting the process of fermentation, acidification or any other decomposition of food. Salting i.e. addition of table salt is a well known method for food preservation and was applied in ancient times for preserving raw mangoes, tamarind, meat, fish etc. Sugar syrup can also act as a preservative. Vinegar is a useful preservative for pickles. Apart from these, sulphur dioxide and benzoic acid can be employed for the preservation of food. The major source of sulphur dioxide is potassium metabisulphite (K2S2O5). It is fairly stable in neutral and alkaline medium but gets decomposed by weak acids such as carbonic, citric, tartane and malic acids. Benzoic acid is used either as such or in the form of sodium benzoate. However, sulphur dioxide has a better preservative action than sodium benzoate against bacteria and moulds. It also retards the development of yeast in juice but fails to arrest their multiplication once the number has reached a high value. Sorne salts of sorbic acid and propionic acid are also being used these days for the preservation of the food.
The use of preservatives must be properly controlled as their indiscriminate use is likely to be harmful. The preservative should not be injurious to health and should be also non-irritant.

16.16. Why is the use of aspartame limited to cold foods and drinks?
Ans: This is because it decomposes at baking or cooking temperatures and hence can be used only in cold foods and drinks as an artificial sweetener

16.17. What are artificial sweetening agents? Give two examples.
Ans: Artificial sweeteners are chemical substances which are sweet in taste but do not add any calories to our body. They are excreted as such through urine. For example, saccharin, aspartame, alitame etc.

16.18. Name the sweetening agent used in the preparation of sweets for a diabetic patient.
Ans: Saccharine, aspartame or alitame may be used in the preparation of sweets for a diabetic patient.

16.19. What problem arises in using alitame as artificial sweetener?
Ans: Alitame is a high potency artificial sweetener.Therefore, it is difficult to control the sweetness of the food to which it is added.

16.20. How are synthetic detergents better than soaps?
Ans: They can be used in hard water as well as in acidic solution. The reason being that sulphonic acids and their calcium and magnesium salts are soluble in water thus they do not form curdy white precipitate with hard water but the fatty acids and their calcium and magnesium salts of soaps are insoluble. Detergents also works in slightly acidic solution due to formation of soluble alkyl hydrogen sulphates. Soaps react with acidic solution to form insoluble fatty acids.

16.21. Explain the following terms with suitable examples:
(i) cationic detergents (ii) anionic detergents and (iii) non-ionic detergents
Ans: (i) Cationic detergents: These are quaternary ammonium salts, chlorides, acetates, bromides etc containing one or more long chain alkyl groups. For example, cetyltrimethyl ammonium chloride.
(ii) Anionic detergents are called so because a large part of their molecules are anions. ‘These are of two types:
(a) Sodium alkyl sulphates: For example, sodium lauryl sulphate, C11H23CH2OSO3 Na+.
(b) Sodium alkylbenzenesulphonates.Vor example, sodium 4-(l-dodecyl) benzenesu Iphphonate (SDS).


(iii) Neutral or non-ionic detergents: These are esters of high molecular mass alcohols with fatty acids. These can also be obtained by treatment of long chain alcohols by with excess of ethylene oxide in presence of a base. For example, polyethylene glycol stearate,CH3(CH2)16COO (CH2CH2O)11 CH2CH2OH Polyethylene glycol stearate.

16.22. What are biodegradable and non-biodegradable detergents? Give one example of each.
Ans: Detergents having straight chain hydrocarbons are easily degraded (or decomposed) by microorganisms and hence are called biodegradable detergents while detergents containing branched hydrocarbon chains are not easily degraded by the microorganisms find hence are called non-biodegradable detergents. Consequently, non-biodegradable detergents accumulate in rivers and water ways thereby causing severe water pollution. Examples of biodegradable detergents are sodium lauryl sulphate, sodium 4-(-l-dodecyl) benzenesulphonate and sodium 4-(2-dodecyl) benzenesulphonate.
Examples of non-biodegradable detergents is sodium 4-(1, 3,5,7 – tetramethyloctyl) benzene sulphonate.

16.23. Why do soaps not work in hard water? (C.B.S.E. Outside Delhi 2009, 2011)
Ans: Soaps are water soluble sodium or potassium salts of higher fatty acids like palmitic acid (C15H31COOH), oleic acid (C17H33COOH) and stearic acid (C17H35COOH). Hard water contains certain calcium and magnesium salts which combine with soaps to form corresponding magnesium compounds. These being insoluble, get separated as curdy white precipitates resulting in wastage of soap.

16.24. Can you use soaps and synthetic detergents to check the hardness of water?
Ans: Soaps get precipitated as insoluble calcium and magnesium soaps in hard water but detergents do not. Therefore, soaps but not synthetic detergents can be used to check the hardness of water.

16.25. Explain the cleansing action of soaps.
Ans: Cleansing action of soaps : Soaps contain two parts, a large hydrocarbon which is a hydrophobic (water repelling) and a negative charged head, which is hydrophillic (water attracting). In solution water molecules being polar in nature, surround the ions & not the organic part of the molecule. When a soap is dissolved in water the molecules gather together as clusters, called micelles. The tails stick inwards & the head outwards. The hydrocarbon tail attaches itself to oily dirt. When water is agitated, the oily dirt tends to lift off from the dirty surface & dissociates into fragments. The solution now contains small globules of oil surrounded detergent molecules. The negatively charged heads present in water prevent the small globules from coming together and form aggregates. Thus the oily dirt is removed from the object.

16.26. If water contains dissolved calcium hydrogencarbonate, out of soaps and synthetic detergents, which one will you use for cleaning clothes?
Ans: Calcium hydrogencarbonate makes water hard. Therefore, soap cannot be used because it gets precipitated in hard water. On the other hand, a synthetic detergent does not precipitate in hard water because its calcium salt is also soluble in water. Therefore, synthetic detergents can be used for cleaning clothes in hard water.

16.27. Label the hydrophilic and hydrophobic parts in the following compounds.
(i)cCH3(CH2)10CH2OSO3 Na+
(ii) CH3(CH2)15 -N+(CH3)3Br
(iii) CH3(CH2)16C00(CH2CH2O)11CH2CH2OH
Ans:

Important Questions for Class 12 Chemistry Chapter 16 Chemistry in Everyday Life Class 12 Important Questions

Chemistry in Everyday Life Class 12 Important Questions Very Short Answer Type

Question 1.
Differentiate between disinfectants and antiseptics. (Delhi 2012)
Answer:

AntisepticsDisinfectants
1. They are chemical substances which prevent the growth of micro-organisms and may even kill them.1. They are chemical substances which kill micro-organisms.
2. They are safe to be applied to the living tissues.2. They are not safe to be applied to the living tissues.
3. They are generally applied on wounds, cuts, ulcers and diseased skin surfaces. Example : Furacin, soframycin, dettol and savlon, 0.2% solution of phenol.3. They are used to kill micro-organisms present in the drains, toilets, floors etc. Example: Phenol (> 1% solution) and chlorine (0.2 to 0.4 ppm).

Question 2.
What are limited spectrum antibiotics? Give one example. (Comptt. Delhi 2012)
Answer:
Those antibiotics which are specific for certain diseases are called limited spectrum antibiotics. Example: Streptomycin for tuberculosis.

Question 3.
Name the important by-products of soap industry. (Comptt. Delhi 2012)
Answer:
Glycerol is the important by-product of soap industry.

Question 4.
Why do we require artificial sweetening agents? (Comptt. All India 2012)
Answer:
To reduce calorie intake and to protect teeth from decaying, we need artificial sweetners.

Chemistry in Everyday Life Class 12 Important Questions Short Answer Type SA-I

Question 5.
What are food preservatives? Name two such substances. (All India 2012)
Answer:
Food preservatives : Food preservatives are the compounds which prevent spoilage of food due to microbial growth.
Two substances : Example : Sodium benzoate, vinegar.

Question 6.
Explain the cleaning action of soap. Why do soaps not work in hard water? (All India 2012)
Answer:
Cleaning action of soap : The cleansing action of soap is due to the fact that soap molecules form micelles around the oil droplets in such a way that hydrophobic part of stearate ions is in the oil droplet and hydrophilic part projects out of the grease droplet like the bristles. Since the polar groups can interact with water, the oil droplet surrounded by stearate ions is now pulled in water and removed from the dirty surface. Thus soap helps in emulsification and washing away of oils and fats.

Reason : Hard water contains calcium and magnesium ions. These ions form insoluble Ca and Mg salts. These salts act as scum. The insoluble scum sticks on the clothes, so the cleaning capacity of soap is reduced when Na or K soaps are dissolved in hard water.

Question 7.
Explain the following terms with suitable examples :
(a) Cationic detergents
(b) Anionic detergents (Comptt. Delhi 2013)
Answer:
(a) Cationic detergents :
(i) Cationic detergents : They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.

(b) Anionic detergents : Those detergents in which large part of their molecules are anions and used in cleansing action, are called anionic detergents.
Example : Sodium alkyl sulphates These are obtained from long straight chain alcohols containing 12-18 carbon atoms by treatment with cone. H2S04 followed by neutralization with NaOH.
Example : Sodium lauryl sulphate.

Chemistry in Everyday Life Class 12 Important Questions Short Answer Type SA-II

Question 8.
Explain the following types of substances with one suitable example, for each case :
(i) Cationic detergents.
(ii) Food preservatives.
(iii) Analgesics. (Delhi 2009)
Answer:
(i) Cationic detergents : They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.

(ii) Food preservatives : They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(iii) Analgesics : Analgesics reduce or abolish pain without causing impairment of consciousness, mental confusion, in coordination or paralysis or some other disturbance of nervous system.
They are of two types :
(a) Non-narcotic analgesics Example : Aspirin
(b) Narcotic analgesics Example : Morphine

Question 9.
How do antiseptics differ from disinfectants? Give one example of each type. (Delhi 2008)
Antiseptics Disinfectants
Answer:

AntisepticsDisinfectants
1. They are chemical substances which prevent the growth of micro-organisms and may even kill them.1. They are chemical substances which kill micro-organisms.
2. They are safe to be applied to the living tissues.2. They are not safe to be applied to the living tissues.
3. They are generally applied on wounds, cuts, ulcers and diseased skin surfaces. Example : Furacin, soframycin, dettol and savlon, 0.2% solution of phenol.3. They are used to kill micro-organisms present in the drains, toilets, floors etc. Example: Phenol (> 1% solution) and chlorine (0.2 to 0.4 ppm).

Question 10.
What are the following substances? Give one example of each type.
(i) Antacid
(ii) Non-ionic detergents
(iii) Antiseptics (All India 2008)
Answer:
(i) Antacid : Those substances which neutralize the excess acid and raise the pH to an appropriate level in stomach are called antacids.
Example : Sodium bicarbonate, Mg(OH)2

(ii) Non-ionic detergents : These are esters of high molecular mass alcohols obtained by reaction between polyethylene glycol and steric acid.
Example :

(iii) Antiseptics : These are chemical substances which prevent the growth of micro-organisms and may even kill them and safe to be applied on living tissues.
Example : Furacin, soframycin etc.

Question 11.
Describe the following substances with one suitable example of each type : (All India 2009)
(i) Non-ionic detergents
(ii) Food preservatives
(iii) Disinfectants
Answer:
(i) Non-ionic detergents : These are esters of high molecular mass alcohols obtained by reaction between polyethylene glycol and steric acid.
Example :

(ii) Food preservatives : They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(iii) Disinfectants :
Disinfectants are chemical compounds which kill microorganisms but are not safe when applied on living organisms.
Example : Phenol, chlorine.

Question 12.
What are the following substances? Give one example of each of them. (All India 2009)
(i) Cationic detergents
(ii) Enzymes
(iii) Sweetening agents
Answer:
(i) Cationic detergents : They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.

(ii) Enzymes : Enzymes are biological catalysts which are chemically globular proteins having high molecular mass and highly specific in their actions due to presence of active sites of definite shape and size on their surfaces so that only specific substrate can fit in them.
Example : Pepsin, amylase

(iii) Sweetening agents : Those chemical substances which are sweet in taste but do not add any calories to our body are called artificial sweetening agents. These are excreted as such through urine.
Example : Saccharin, aspartame etc.

Question 13.
What are analgesic medicines? How are they classified and when are they commonly recommended for use? (Delhi 2010)
Answer:
Analgesic medicine : Drugs which reduce or abolish pain without causing reduction of consciousness, mental confusion, incoordination or paralysis or some other disorder of the nervous system are called analgesic medicines.
They are classified into the following two categories :
(i) Non-narcotic (non-addictive) drugs Example : Aspirin, Ibuprofen
(ii) Narcotic (addictive) drugs Example : Morphine, Heroin.
They are recommended with proper prescription because they are habit forming drugs.

Question 14.
Explain the following terms with one suitable example in each case.
(i) Cationic detergents
(ii) Enzymes
(iii) Antifertility drugs (Delhi 2010)
Answer:
(i) Cationic detergents : They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.

(ii) Enzymes :
The enzymes may be defined as bio-catalysts which catalyse the bio-chemical reactions in the living organisms.
Example : Pepsin and Amylase.

(iii) Antifertility drugs : Chemical substances, which are used to check pregnancy in women, are called antifertility drugs or birth control pills or oral contraceptives. These control the female menstrual cycle and ovulation.
Example : Norethindrone, Ethinyl estradol, Mestranol.

Question 15.
Explain the following terms with one example in each case :
(i) Food preservatives
(ii) Enzymes
(iii) Detergents (Delhi 2010)
Answer:
(i) Food preservatives : They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(ii) Enzymes : The enzymes may be defined as bio-catalysts which catalyse the bio-chemical reactions in the living organisms.
Example : Pepsin and Amylase.

(iii) Detergents : They may be defined as ammonium, sulphonate or sulphate salts of long chain hydrocarbons containing 12-18 carbon atoms.
Example : Sodium lauryl sulphate.

Unlike soaps they are non-biodegradable and hence cause water pollution but they can be conveniently used even in hard water.

Question 16.
What are analgesic drugs? How are they classified and when are they usually recommended for use? (Delhi 2010)
Answer:
Analgesic drugs : These drugs are the chemical substances which are given to relieve body pains. These act on the central nervous system.

These are classified as Narcotics i.e. habit forming and non-narcotics i.e. not habit forming.
Examples of Narcotics : Opium which contains alkaloids such as Codeine and Morphine.
Examples of Non-Narcotics : Aspirin and Ibuprofen.

Question 17.( chemistry in everyday life )
Explain the following terms with an example for each :
(i) Antibiotics
(ii) Antiseptics
(iii) Analgesics (Delhi 2010)
Answer:
(i) Antibiotics : Those chemical substances which are produced completely or partially by chemical synthesis in low concentration and either kill or inhibit the growth of microorganisms by intervening in their metabolic processes, are known as antibiotics.
Examples:
Tetracycline ➝ Bacteriostatic antibiotics, Penicillin Bactericidal antibiotics

(ii) Antiseptics :
These are chemical substances which prevent the growth of micro-organisms and may even kill them and safe to be applied on living tissues.
Example : Furacin, soframycin etc.

(iii) Analgesics :
Analgesic drugs : These drugs are the chemical substances which are given to relieve body pains. These act on the central nervous system.

These are classified as Narcotics i.e. habit forming and non-narcotics i.e. not habit forming.

Examples of Narcotics : Opium which contains alkaloids such as Codeine and Morphine.
Examples of Non-Narcotics : Aspirin and Ibuprofen.

Question 18.( chemistry in everyday life )
Describe the following giving one example for each :
(i) Detergents
(ii) Food preservatives
(iii) Antacids (Delhi 2010)
Answer:
(i) Detergents :
They may be defined as ammonium, sulphonate or sulphate salts of long chain hydrocarbons containing 12-18 carbon atoms.
Example : Sodium lauryl sulphate.
Unlike soaps they are non-biodegradable and hence cause water pollution but they can be conveniently used even in hard water.

(ii) Food preservatives: They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(iii) Antacids : The substances which neutralize the excess acid and raise the pH to an appropriate level in the stomach are called antacids.
Example: Sodium bicarbonate, Ranitidine etc.

Question 19.( chemistry in everyday life )
Explain the following terms with one suitable example for each :
(i) A sweetening agent for diabetic patients
(ii) Enzymes
(iii) Analgesics (Delhi 2010)
Answer:
(i) The sweetening agent used in the preparation of sweets for a diabetic patient is Saccharin.

(ii) Enzymes :
The enzymes may be defined as bio-catalysts which catalyse the bio-chemical reactions in the living organisms.
Example : Pepsin and Amylase.

(iii) Analgesics :

Analgesic drugs : These drugs are the chemical substances which are given to relieve body pains. These act on the central nervous system.

These are classified as Narcotics i.e. habit forming and non-narcotics i.e. not habit forming.
Examples of Narcotics : Opium which contains alkaloids such as Codeine and Morphine.
Examples of Non-Narcotics : Aspirin and Ibuprofen.

Question 20.( chemistry in everyday life )
Answer the following questions :
(i) Why do soaps not work in hard water?
(ii) What are the main constituents of dettol?
(iii) How do antiseptics differ from disinfectants? (Delhi 2010)
Answer:
(i) Hard water contains insoluble calcium and magnesium chlorides which forms insoluble precipitate (scum) with soap and thus cannot be rinsed off easily.
(ii) Dettol is mixture of chloroxylenol and α-terpineol in a suitable solvent.
(iii)

AntisepticsDisinfectants
1. Antiseptics either kill or prevent the growth of micro­organisms.1. Disinfectants kill the microbes definitely.
2. Antiseptics do not cause harm to the living tissues.2. Disinfectants are toxic to the living tissues and thus cause harm to the tissues of the skin etc.

Question 21.( chemistry in everyday life )
What are the following substances? Give one example of each.
(i) Food preservatives
(ii) Synthetic detergents
(iii) Antacids (All India 2010)
Answer:
(i) Food preservatives : They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(ii) Synthetic detergents : Synthetic detergents are cleansing agents which have all the properties of soap but which actually do not contain any soap.
Example : Sodium lauryl sulphate (or any one other)

(iii) Antacids :
The substances which neutralize the excess acid and raise the pH to an appropriate level in the stomach are called antacids.
Example: Sodium bicarbonate, Ranitidine etc.

Question 22.( chemistry in everyday life )
(a) Differentiate between a disinfectant and an antiseptic. Give one example of each.
(b) What is tincture of iodine and what is it used for? (All India 2010)
Answer:
(a)

AntisepticsDisinfectants
1. They are chemical substances which prevent the growth of micro-organisms and may even kill them.1. They are chemical substances which kill micro-organisms.
2. They are safe to be applied to the living tissues.2. They are not safe to be applied to the living tissues.
3. They are generally applied on wounds, cuts, ulcers and diseased skin surfaces. Example : Furacin, soframycin, dettol and savlon, 0.2% solution of phenol.3. They are used to kill micro-organisms present in the drains, toilets, floors etc. Example: Phenol (> 1% solution) and chlorine (0.2 to 0.4 ppm).

(b) Tincture of iodine is 2-3% solution of iodine in alcohol and water.

  • Use : It is used as a powerful antiseptic and applied on wounds to kill and prevent growth of micro-organisms.

Question 23.( chemistry in everyday life )
What are the following substances? Give one example of each one of them. (Delhi 2012)
(i) Tranquilizers
(ii) Food preservatives
(iii) Synthetic detergents
Answer:
(i) Tranquilizers : Tranquilizers are chemical compounds used for the treatment of stress and mild or even severe mental diseases. Example : Equanil, meprobamate, veronal. (any one)

(ii) Food preservatives : Food preservatives are the compounds which prevent spoilage of food due to microbial growth.
Example : Sodium benzoate, table salt, vegetable oils etc.

(iii) Synthetic detergents : Synthetic detergents are cleansing agents which have all the properties of soap but which actually do not contain any soap.
Example : Sodium lauryl sulphate.

Question 24.( chemistry in everyday life )
Explain the following terms giving one example of each type : (Delhi 2012)
(i) Antacids
(ii) Disinfectants
(iii) Enzymes
Answer:
(i) Antacids: Those substances which neutralize the excess acid and raise the pH to an appropriate level in stomach are called antacids.
Example : Sodium bicarbonate, Mg(OH)2

(ii) Disinfectants : Disinfectants are chemical compounds which kill microorganisms but are not safe when applied on living organisms.
Example : Phenol, chlorine.

(iii) Enzymes : Enzymes are biological catalysts which are chemically globular proteins having high molecular mass and highly specific in their actions due to presence of active sites of definite shape and size on their surfaces so that only specific substrate can fit in them. Example : Pepsin, amylase

Question 25.( chemistry in everyday life )
What are the following substances ? Give one example of each.
(i) Antihistamines
(ii) Tranquilizers
(iii) Broad spectrum antibiotics (Comptt. Delhi 2012)
Answer:
(i) Antihistamines : Antihistamines are amines which are used as drugs to control the allergy effects produced by histamines. Example : Terfenadine

(ii) Tranquilizers : Tranquilizers are a class of chemical compounds used for the treatment of stress, and mild or even severe mental disease.
Example : Equanil.

(iii) Broad spectrum antibiotics : Antibiotics which kill or inhibit a wide range of Gram¬positive and Gram-negative bacteria are said to be broad spectrum antibiotics.
Example : Chloroamphenicol.

Question 26.( chemistry in everyday life )
(a) How do antiseptics differ from disinfectants? Give one example of each. (Give two differences)
(b) Why do soaps not work in hard water? (Comptt. Delhi 2012)
Answer:
(a)

AntisepticsDisinfectants
1. They are chemical substances which prevent the growth of micro-organisms and may even kill them.1. They are chemical substances which kill micro-organisms.
2. They are safe to be applied to the living tissues.2. They are not safe to be applied to the living tissues.
3. They are generally applied on wounds, cuts, ulcers and diseased skin surfaces. Example : Furacin, soframycin, dettol and savlon, 0.2% solution of phenol.3. They are used to kill micro-organisms present in the drains, toilets, floors etc. Example: Phenol (> 1% solution) and chlorine (0.2 to 0.4 ppm).
chemistry in everyday life

(b) Hard water contains Ca+2 and Mg+2 ions. These ions form insoluble calcium and magnesium salts respectively, when Na or K soaps are dissolved in hard water. These insoluble salt, separate as scum which adheres to fabric, thereby making soap ineffective for cleansing action.

Question 27.( chemistry in everyday life )
What are the following substances ? Give one example of each.
(i) Analgesics
(ii) Antibiotics
(iii) Tranquilizers (Comptt. All India 2012)
Answer:
(i) Analgesics : Analgesics reduce or abolish pain without causing impairment of consciousness, mental confusion, incoordination or paralysis or some other disturbances of nervous system.
Example : Aspirin.

(ii) Antibiotics : Antibiotic refers to a substance produced wholly or partly by chemical synthesis which in low concentration inhibits the growth or destroys microorganisms by intervening in their metabolic processes.
Example : Penicillin.

(iii) Tranquilizers : Tranquilizers are a class of chemical compounds used for the treatment of stress, and mild or even severe mental disease.
Example : Equanil.

Question 28.( chemistry in everyday life )
What are the following substances? Give one example of each.
(i) Broad Spectrum antibiotics
(ii) Narcotic analgesics
(iii) Synthetic detergents (Comptt. All India 2012)
Answer:
(i) Broad spectrum antibiotics : Antibiotics which kill or inhibit a wide range of Gram¬positive and Gram-negative bacteria are said to be broad spectrum antibiotics.
Example : Chloroamphenicol.

(ii) Narcotic analgesics : Narcotic analgesics are administered in medicinal doses, relieve pain and produce sleep,
Example : Morphine and many of its homologues.

(iii) Synthetic detergents : Synthetic detergents are cleansing agents which have all the properties of soap but which actually do not contain any soap.
Example : Sodium lauryl sulphate.

Question 29.( chemistry in everyday life )
(a) Which one of the following is a food preservative?
Equanil, Morphine, Sodium benzoate
(b) Why is bithional added to soap?
(c) Which class of drugs is used in sleeping pills? (Delhi 2013)
Answer:
(a) Sodium Benzoate: It is a food preservative.
(b) Bithional acts as deodorant in soaps, hence it works as an antiseptic agent and reduces the odours produced by bacterial decomposition of organic matter on the skin.
(c) Tranquilizers like barbiturates are used in sleeping pills.

Question 30.
(i) What class of drug is Ranitidine?
(ii) If water contains dissolved Ca2+ ions, out of soaps and synthetic detergents, which will you use for cleaning clothes?
(iii) Which of the following is an antiseptic? 0.2% phenol, 1% phenol (All India 2013)
Answer:
(i) Ranitidine is an Antacid.
(ii) We will use synthetic detergents because they can produce lather with the hard water containing Ca2+ ions.
(iii) 0.2% phenol acts as an antiseptic.

Question 31.( chemistry in everyday life )
(a) How do antiseptics differ from disinfectants? Give one example of each.
(b) What are tranquilizers? Give one example. (Comptt. All India 2013)
Answer:
(a) AntisepticsDisinfectants1. They are chemical substances which prevent the growth of micro-organisms and may even kill them.1. They are chemical substances which kill micro-organisms.2. They are safe to be applied to the living tissues.2. They are not safe to be applied to the living tissues.3. They are generally applied on wounds, cuts, ulcers and diseased skin surfaces. Example : Furacin, soframycin, dettol and savlon, 0.2% solution of phenol.3. They are used to kill micro-organisms present in the drains, toilets, floors etc.
Example: Phenol (> 1% solution) and chlorine (0.2 to 0.4 ppm).

(b) Tranquilizers : Drugs which are used for the treatment of stress, fatigues, mild and severe mental diseases are called tranquilizers.
Example : Iproniazid, Phenelzine etc.

Question 32.( chemistry in everyday life )
Explain the following and give one example for each :
(i) Broad spectrum antibiotics
(ii) Antipyretics
(iii) Anti-oxidants (Comptt. All India 2013)
Answer:
(i) Broad spectrum antibiotics : Antibiotics which kill or inhibit a wide range of Gram¬positive and Gram-negative bacteria are called broad spectrum antibiotics.
Example : Chloro-amphical

(ii) Antipyretics : Chemicals, which are used to bring down the body temperature during high fever, are called antipyretics Example : Paracetamol, Aspirin etc.

(iii) Anti-oxidants : Those molecules, which inhibit the oxidation of other molecules, are called anti-oxidants
Example : Thiols, Ascorbic acid etc.

Question 33.( chemistry in everyday life )
(i) Give two examples of macromolecules that are chosen as drug targets.
(ii) What are antiseptics? Give an example.
(iii) Why is use of aspartame limited to cold foods and soft drinks? (Delhi 2014)
Answer:
(i) Carbohydrates and proteins

(ii)  Antiseptics : These are chemical substances which prevent the growth of micro-organisms and may even kill them and safe to be applied on living tissues.
Example : Furacin, soframycin etc.

(iii) Because it decomposes at baking or cooking temperature.

Question 34.( chemistry in everyday life )
(i) Name the sweetening agent used in the preparation of sweets for a diabetic patient.
(ii) What are antibiotics? Give an example.
(iii) Give two examples of macromolecules that are chosen as drug targets. (Delhi 2014)
Answer:
(i) Saccharin is used for a diabetic patient for preparation of sweets.

(ii) Antibiotics :
Those chemical substances which are produced completely or partially by chemical synthesis in low concentration and either kill or inhibit the growth of microorganisms by intervening in their metabolic processes, are known as antibiotics.
Examples:
Tetracycline ➝ Bacteriostatic antibiotics, Penicillin Bactericidal antibiotics

(iii) Carbohydrates, proteins, nucleic acid etc.

Question 35.( chemistry in everyday life )
(i) What are disinfectants? Give an example.
(ii) Give two examples of macromolecules that are chosen as drug targets.
(iii) What are anionic detergents? Give an example. (Delhi 2014)
Answer:
(i) Disinfectants : Disinfectants are chemical compounds which kill microorganisms but are not safe when applied on living organisms.
Example : Phenol, chlorine.

(ii) Macromolecules used as drug targets are carbohydrates, proteins, nucleic acid and lipids.

(iii) Anionic detergents.
Those detergents in which large part of their molecules are anions and used in cleansing action, are called anionic detergents.
Example : Sodium alkyl sulphates These are obtained from long straight chain alcohols containing 12-18 carbon atoms by treatment with cone. H2SO4 followed by neutralization with NaOH.
Example : Sodium lauryl sulphate.

Question 36.( chemistry in everyday life )
Explain the following terms with a suitable example for each:
(i) Disinfectants
(ii) Antacids
(iii) Food preservatives (Comptt. Delhi 2014)
Answer:
(i) Disinfectants : These are the chemical substances which are used for killing or
preventing the growth of micro-organisms but they are not safe for living tissues.

(ii) Antacid : Those substances which neutralize the excess acid and raise the pH to an appropriate level in stomach are called antacids.
Example : Sodium bicarbonate, Mg(OH)2

(iii) Food preservatives : They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

Question 37.( chemistry in everyday life )
What are the following? Give one example of each.
(i) Sweetening agents
(ii) Food preservatives
(iii) Antibiotics (Comptt. Delhi 2014)
Answer:
(i) Sweetening agent : Those chemical substances which are sweet in taste but do not add any calories to our body are called artificial sweetening agents. These are excreted as such through urine.
Example ; Saccharin, aspartame etc.

(ii) Food preservatives: They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(iii) Antibiotics : Those chemical substances which are produced completely or partially ’by chemical synthesis in low concentration and either kill or inhibit the growth of micro-organisms by intervening in their metabolic processes, are known as antibiotics.
Example : Tetracycline, Vancomycin

Question 38.( chemistry in everyday life )
What are biodegradable and non-biodegradable detergents? Give one example of each. (Comptt. Delhi 2014)
Answer:
Biodegradable detergents : Detergents, having straight hydrocarbon chains are easily degraded or decomposed by micro-organism, are known as biodegradable detergents.
Example : Sodium lauryl sulphate.

Non-biodegradable detergents : Detergents containing branched hydrocarbon chains and are not easily decomposed by the micro-organisms, are known as non-biodegradable detergents.
Example : Sodium 4 – (1, 3, 5, 7-tetramethyloctyl) benzene sulphonate.

Question 39.( chemistry in everyday life )
What is meant by the following terms? Explain with an example for each.
(i) Target molecules as used in medicinal chemistry
(ii) Food preservative
(iii) Non-ionic detergents (Comptt. All India 2014)
Answer:
(i) Drugs interact with macromolecules like proteins, carbohydrates, lipids etc. and are called as target molecules.

(ii) Food preservatives: They are used to prevent spoilage of food due to microbial growth.
Example : Table salt, vegetable oils, sodium benzoate etc.

(iii) Non-ionic detergents : These are esters of high molecular mass alcohols obtained by reaction between polyethylene glycol and steric acid.
Example :

Question 40.( chemistry in everyday life )
Answer the following questions :
(i) Why should medicines not be taken without consulting a doctor?
(ii) What is meant by ‘broad spectrum antibiotics’?
(iii) What are the main constituents of Dettol? (Comptt. All India 2014)
Answer:
(i) Because medicines can cause harm to human body if a person does not know its physiological function on body.

(ii) Antibiotics which kill or inhibit a wide range of gram positive and gram negative bacteria, are called broad spectrum antibiotics.

(iii) Dettol is mixture of chloroxylenol and a-terpineol in a suitable solvent.

Question 41.( chemistry in everyday life )
Answer the following :
(i) Why is the use of aspartame limited to cold foods and drinks?
(ii) How do antiseptics differ from disinfectants?
(iii) Why do soaps not work in hard water? (Comptt. All India 2014)
Answer:
(i) Use of aspartame is limited to cold foods and soft drinks because it is unstable at cooking temperature.

(ii)

AntisepticsDisinfectants
1. They are chemical substances which prevent the growth of micro-organisms and may even kill them.1. They are chemical substances which kill micro-organisms.
2. They are safe to be applied to the living tissues.2. They are not safe to be applied to the living tissues.
3. They are generally applied on wounds, cuts, ulcers and diseased skin surfaces. Example : Furacin, soframycin, dettol and savlon, 0.2% solution of phenol.3. They are used to kill micro-organisms present in the drains, toilets, floors etc. Example: Phenol (> 1% solution) and chlorine (0.2 to 0.4 ppm).
chemistry in everyday life

(iii) Hard water contains insoluble calcium and magnesium chlorides which forms insoluble ppt (scum) with soap and thus cannot be rinsed off easily.

Question 42.( chemistry in everyday life )
Define the following:
(i) Anionic detergents
(ii) Broad spectrum antibiotics
(iii) Antiseptic (Delhi 2017)
Answer:
(i) Anionic detergents : Those detergents in which large part of their molecules are anions and used in cleansing action, are called anionic detergents.
Example : Sodium alkyl sulphates These are obtained from long straight chain alcohols containing 12-18 carbon atoms by treatment with cone. H2S04 followed by neutralization with NaOH.
Example : Sodium lauryl sulphate.

(ii) Broad spectrum antibiotics : Antibiotics which kill or inhibit a wide range of Gram¬positive and Gram-negative bacteria are said to be broad spectrum antibiotics.
Example : Chloroamphenicol.

(iii) Antiseptics are the chemicals which either kill or prevent growth of microbes on living tissues.

Question 43.( chemistry in everyday life )
Define the following:
(i) Cationic detergents
(ii) Narrow spectrum antibiotics
(iii) Disinfectants (Delhi 2017)
Answer:
(i) Cationic detergents. They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.
Example: Cetyltrimethyl ammonium bromide —

(ii) Narrow spectrum antibiotics. Narrow spectrum antibiotics are those antibiotics which are mainly effective against gram positive or gram negative bacteria.

(iii) Disinfectants. Disinfectants kill or prevent growth of microbes and are applied on inanimate/non living objects.
Example: Phenol

Question 44.( chemistry in everyday life )
Define the following:
(i) Anionic detergents
(ii) Limited spectrum antibiotics
(iii) Tranquilizers (Delhi 2017)
Answer:
(i) Those detergents in which large part of their molecules are anions and used in cleansing action, are called anionic detergents.
Example: Sodium alkyl sulphates
(ii) Limited spectrum antibiotics are those which are effective against a single organism or disease.
(iii) Tranquilizers are class of chemicals used for treatment of stress or mild or severe mental diseases.

Question 45.( chemistry in everyday life )
Define the following
(a) Anionic detergents
(b) Limited spectrum antibiotics
(c) Antiseptics (All India 2017)
Answer:
(a) Anionic detergents : Those detergents in which large part of their molecules are anions and used in cleansing action, are called anionic detergents.
Example : Sodium alkyl sulphates These are obtained from long straight chain alcohols containing 12-18 carbon atoms by treatment with cone. H2S04 followed by neutralization with NaOH.
Example : Sodium lauryl sulphate.

(b) Limited spectrum antibiotics are effective against a single organism or disease, e.g., Streptomycin.
(c) Antiseptics are the chemicals which either kill or prevent growth of microbes on living tissues, e.g., Penicillin.

Question 46.( chemistry in everyday life )
Define the following:
(a) Anionic detergents
(b) Narrow spectrum antibiotics
(c) Antacids (All India 2017)
Answer:
(a) Anionic detergents : Those detergents in which large part of their molecules are anions and used in cleansing action, are called anionic detergents.
Example : Sodium alkyl sulphates These are obtained from long straight chain alcohols containing 12-18 carbon atoms by treatment with cone. H2S04 followed by neutralization with NaOH.
Example : Sodium lauryl sulphate.

(b) Narrow spectrum antibiotics are those which are effective against either gram positive or gram negative bacteria.

(c) Antacids are chemical compounds which are used for the treatment of excess acid produced in the stomach.

Question 47.( chemistry in everyday life )
Define the following:
(a) Cationic detergents
(b) Broad spectrum antibiotics
(c) Tranquilizers (All India 2017)
Answer:
(a)
(i) Cationic detergents. They are quaternary
ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.
Example: Cetyltrimethyl ammonium bromide —

(ii) Narrow spectrum antibiotics. Narrow spectrum antibiotics are those antibiotics which are mainly effective against gram positive or gram negative bacteria.

(iii) Disinfectants. Disinfectants kill or prevent growth of microbes and are applied on inanimate/non living objects.
Example: Phenol

(b) Broad spectrum antibiotics. Antibiotics which kill or inhibit a wide range of gram-positive and gram-negative bacteria.

(c) Tranquilizers. Chemical compounds used for the treatment of stress and mild or severe mental diseases.

Question 48. ( chemistry in everyday life )
Write the therapeutic action of following on human body and mention the class of drugs to which each of these belong:
(i) Ranitidine
(ii) Morphine
(iii) Aspirin (Comptt. Delhi 2017)
Answer:
(i) Ranitidine belongs to antacids and it neutralizes the excess acid and raises the pH to an appropriate level in stomach.

(ii) Morphine belongs to narcotic analgesics and it relieves pain and produces sleep even when taken in small dose.

(iii) Aspirin belongs to non-narcotic analgesics and it inhibits the synthesis of compounds which stimulate inflammation in the tissues and cause pain. Aspirin relieves pain and reduces fever.

Question 49. ( chemistry in everyday life )
Write the therapeutic action of following on human body and mention the class of drugs to which each of the these belong:
(i) Equanil
(ii) Aspirin
(iii) Chloramphenicol (Comptt. Delhi 2017)
Answer:
(i) Equanil belongs to the class of tranquilizers and it is used in controlling depression and hypertension.

(ii) Aspirin belongs to non-narcotic analgesics and it inhibits the synthesis of compounds which stimulate inflammation in the tissues and cause pain. Aspirin reduces pain and fever.

(iii) Chloramphenicol belongs to antibiotics and it is used for treatment of typhoid. It kills or inhibits the growth of micro-organisms.

Question 50. ( chemistry in everyday life )
(i) Name a substance which can be used as an antiseptic as well as disinfectant.
(ii) Name an artificial sweetener whose use is limited to cold foods and drinks.
(iii) What are cationic detergents? (Comptt. All India 2017)
Answer:
(i) Phenol
(ii) Aspartame
(iii) Cationic detergents. They are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions and the cationic part possess a long hydrocarbon chain, and a positive charge on nitrogen atom. Therefore they are called cationic detergents.
Example: Cetyltrimethyl ammonium bromide —

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