Explain why alkyl halides are generally not prepared in the laboratory by free radical halogenation of alkanes.

Explain why chorination of n-butane in presence of light at 298 K gives a mixture of 72% of 2-chlorobutane and 28 % of 1-chlorobutane.

Wurtz reaction falils in case of tert-alkyl halides. Explain.

Explain the following in one or two sentences
(i) Displacement of cyanic and amide ion is never observed in nucleophilic substitution reactions.
(ii) RCI is hydrolysed to ROH slowly but the reaction is rapid if a catalytic amount of KI is added to the reaction mixture.

(R)-2- Bromooctane reacts with NaSH to form (S)-2- octanethiol with inversion of configuration at the stereocentre.How can we obtain (R)-2 octanethiol from (R)-2-bromoctane?

Some halogen containing compounds are useful in daily life. Some compounds of this class are responsible for exposure of flora and fauna to more and more of UV light which causes destruction to a great extent. Name the class of these halo compounds. In your opinion, what should be done to minimise harmful effects of these compounds.

Haloalkanes contain halogen atoms (s) attached to the sp³-hybridised carbon atom of an alkyl group. Many halogen containing organic compounds occur in nature and some of them are clinically useful.
(i) Prove the importance of halogen containing organic compounds with the help of three examples.
(ii) Mention the values associated with your reply.

Carbon compounds containing more than one halogen atom are usually called polyhalogen compounds. Polyhalogen compounds are useful in industry and agriculture. One of the important polyhalogen compound is used as an insecticide.
(i) Name the polyhalogen compound for which Paul Muller won the Nobel Prize in medicine and physiology. Draw its structure also.
(ii) Why is the use of DDT banned in some countries?
(iii) What values do you derive from the answer of above question?

Benzene on reaction with HOCI in presence of an acid produces organic compound (A), (A) on treatment with NaNH₂/liq. NH₃ furnishes another organic compound (B). (B) on treatment with HBF₄ affords an organic compound (C) wich on heating with NaNO₂ gives organic compound (D). Identify (A), (B), (C) and (D).