CBSE Class 12 Chemistry Important Questions Chapter 10 – Haloalkanes and Haloarenes

1 Mark Questions

1. Give IUPAC names of following compounds      

Ans.(i). 1, 3- Dibromobutane

(ii). 1- Cholopropan-2-ol

(iii). 2, 3 – Dibromo-1-chloro-3-methylpentane

(iv). 2-Choloro-3-ethyl-2-methyl pentane

(v). 1-Chloro-2-phenylethane

(vi). 1-Chloro-1-phenyl ethane

(vii). 1, 2, 3, 4, 5, 6- hexachlorocyclohexane

(viii). 2, 2- Dihexyl 1, 1, 1-Trichloro ethane

(ix). 4, 4-dibromobiphenyl

(x). 1, 3-Dibromo -3- methyl butane

(2). Give the structures of following.:

(i). 1,3-Dichloro -2-(bromomethyl) propane

(ii). Isobutylchloride

(iii). Ortho bromotoluene

(iv). 1 – Bromo – 4 – chlorobutane

(v). 3 – Bromo – 5 – chloro – 3,5 – dimethyloctane

(vi). 2,3 – Dibromo – 1 – chloro -3- methylpentane

(vii). 2 – Chloro – 3 – ethyl -1, 4- pentadieme

(viii). 2,3 – Dibromo – 1 – chloro -3- methylpentane

(ix). 2 – Chloro – 1 – phemylpropane

(x). Tert – butylchloride

5. Which of the following will show optical is omerism

1 – bromobutane or 2 – bromobutane?

Ans. 

7. Give an example of    

 (a)  Fittig reaction             

     (b)  Finkelstein reaction.

Ans.  (a) Fittig reaction

 

2. Phenol cannot be converted to chlorobenzene by reacting with HCl.

Ans. In phenol, due to resonance, the carbon –oxygen bond has a partial double bond character and is difficult to break being stronger than a single bond. Therefore it can not be converted to chlorobenzene by reacting with HCl.

p- dichlorebenzene is having symmetrical structure therefore it can fit better into the crystal lattice which increases its melting point.

The attack of nucleophile can result in product which is a mixture of compounds both with same configuration and inverted configuration.

8. Chloroform is stored in dark coloured bottles.

Ans. Chloroform gets oxidsed slowly by air in the presence of light to an extremely poisonous gas phosgene. Therefore to avoid any exposure to air and sunlight, it is kept in dark coloured bottles.

12. How many aromatic isomers are possible for the formula ? Write the structure and names.