Question

Match column A with column B in the proper sequence.

Column A	Column B
$P.$ Chlorination in presence of sunlight	$\left( 1 \right)$ Alcohols
$Q.$ Addition of ${H_2}$to give saturated compounds	$\left( 2 \right)$ Carboxylic Acid
$R.$ Formation of alkene on heating with ${\text{con}}{\text{. }}{H_2}S{O_4}$	$\left( 3 \right)$ Alkenes
$S.$ Reaction with alcohol to give esters	$\left( 4 \right)$ Alkanes

Answer 1

Hint: Chlorination process involves less amount of heat .This heat is in the form of sunlight. Saturated compounds are those which contain a single carbon to carbon bond. Hydrolysis of a compound brings unsaturation. Recall reactants of Ester formation .

Complete answer:
Firstly we will take statement P.
Chlorination is a free radical substitution reaction which takes place in the presence of sunlight. So the free radical formation takes place in alkanes . Also there is no extra heat given in Chlorination .Therefore it is hard to break double bonds in alkenes. Hence Chlorination will take place only in alkanes.
$P\xrightarrow{{}}{\text{ }}\left( 4 \right)$
Considering statement Q.
The addition of ${H_2}$takes place only in unsaturated compounds. Alcohol shows no effect in addition to ${H_2}$ to it. Also the carboxylic acid shows no effect on adding ${H_2}$to it . Alkenes undergo hydrogenation in addition of ${H_2}$to it.
$alkenes{\text{ + }}{{\text{H}}_2}{\text{ }}\xrightarrow{{}}{\text{ alkanes}}$
Therefore , $Q\xrightarrow{{}}{\text{ }}\left( 3 \right)$
 Considering statement R.
${\text{con}}{\text{. }}{H_2}S{O_4}$ is a dehydrating agent used to remove water molecules from the given compounds .Since alkanes and alkenes do not contain any water molecules .Thus no effect on alkanes and alkenes .Also it do not show any effect on carboxylic acids too. But in the case of alcohol it dehydrates the water molecule from it.
$alcohol{\text{ + con}}{\text{. }}{{\text{H}}_2}S{O_4}{\text{ }}\xrightarrow{{}}{\text{ alkene + }}{{\text{H}}_2}O$
 Therefore , $R\xrightarrow{{}}{\text{ }}\left( 1 \right)$
Considering statement S.
For ester formation we need alcohol and carboxylic acid to form an ester.
$S\xrightarrow{{}}{\text{ }}\left( 2 \right)$
Therefore the match will be :
$P\xrightarrow{{}}{\text{ }}\left( 4 \right)$
$Q\xrightarrow{{}}{\text{ }}\left( 3 \right)$
$R\xrightarrow{{}}{\text{ }}\left( 1 \right)$
$S\xrightarrow{{}}{\text{ }}\left( 2 \right)$

Note:
Ester formation reactions must be learned while solving the question. Hydrogenation is an additional reaction. There are other dehydrating agents present like con. HCl and many others. In dilute form it does not act dehydrating. Then it takes aqueous form.