Question

Complete the following reaction: $C{{H}_{3}}COC{{H}_{3}}+N{{H}_{2}}N{{H}_{2}}\xrightarrow{KOH/glycol}$

Answer 1

Hint: The given is a reduction of ketone.
Glycol is used as a solvent in the reaction.

Complete step by step answer:
- In the question a reaction of ketone with hydrazine is given along with KOH and glycol and we have to predict the final product that is formed.
- First analyze the reactants given and the reagents that are used in the chemical reaction which may give an idea about the final product of the reaction.
As in the hint section it is given that the chemical reaction happening here is a reduction reaction.
- We are very familiar with the term reduction reaction in which we add the hydrogen molecule to the reactant molecule to get the final product
- If we compare the reactants used here, the reactant undergoing a change is a propanone molecule i.e. a ketone. So a ketone is getting reduced and the reducing agent used here is hydrazine.
The hydrogen molecule from hydrazine molecule is added to the ketone.
- We are very familiar with the reaction in which the carbonyl group in the ketone or aldehyde molecule gets reduced with the aid of hydrazine molecule as the reducing agent and the glycol is used as the solvent. The reaction is the Wolff-Kishner reduction reaction.
- In Wolff-Kishner reduction reaction the carbonyl group in aldehyde or ketone undergoes the complete reduction to yield the corresponding alkane.
A carbonyl group gets reduce to $-C{{H}_{2}}$ group
$-C=O\to -C{{H}_{2}}$
As here the ketone is propanone , since there are three C present.The propane undergoes complete reduction to yield the corresponding alkane which is propane.

Note: If the reagent given is Zn-Hg along with con.HCl, then also the carbonyl carbon in ketone and aldehyde molecule undergo reduction reaction,but the byproduct is water and the chemical reaction is called as Clemmenson reduction reaction. Often students gets confused between the reagents while naming the reaction.