Question

Ketones can be prepared by:
This question has multiple correct options
(a) heating calcium propionate with calcium formate
(b) dry crystallization of fused calcium acetate
(c) hydrolysis of propylidene chloride with alkali
(d) action of dialkyl cadmium on acid chloride

Answer 1

Hint In order to find that by which method we can prepare the ketones, you should know about the different methods of the preparation of ketones and then you can easily answer the given statement.

Complete step by step answer:
First of let’s discuss what ketones are. Ketones are the organic compounds which consist of the $C=O$ group in their compounds and their functional group is also known as the ketonic group.
If the two groups are the same in a ketone, then the ketone is called the simple ketone. On the other hand, if the two groups are different , the ketone is called a mixed ketone.
Now considering the statement as;
Ketones can be prepared by the following methods;
1. dry crystallization of fused calcium acetate:- the reaction occurs as;
${{(HOOC)}_{2}}Ca+{{(C{{H}_{3}}COO)}_{2}}Ca\xrightarrow{dry\text{ }distillation}HCHO+C{{H}_{3}}COC{{H}_{3}}+C{{H}_{3}}CHO$
2.From acyl chlorides:- Ketones can be prepared from acyl chlorides by treating with dialkyl cadmium. The general reaction occurs as;
$2RCOCl+{{R}_{2}}Cd\xrightarrow{dry\text{ }ether}2R-CO-R+CdC{{l}_{2}}$
While by heating calcium propionate with calcium formate and on hydrolysis of propylidene chloride with alkali, the product obtained is aldehyde and not ketone.
So, thus, Ketones can be prepared by dry crystallization of fused calcium acetate and action of dialkyl cadmium on acid chloride.

Hence, options (b) and (d) are correct.

Note: Ketones have slightly higher boiling point than the aldehydes. This is due to the presence of two electrons releasing groups around the carbonyl carbon which makes them more polar.