Predict the products in the given reaction:
Answer & explanation
Correct answer: option 3
The correct answer is option 3. 
Since m-chlorobenzaldehyde does not contain \(\alpha \)- hydrogen thus with 50% KOH it undergoes the Cannizzaro reaction. The Cannizzaro reaction for the m-chlorobenzaldehyde is given as:
Since it is a disproportionation reaction so one molecule of m-chlorobenzaldehyde is reduced to m-chlorobenzyl alcohol at the cost of others which is oxidized potassium m-chlorobenzoate.
Mechanism of the reaction: Cannizzaro reaction is an example of a hydride transfer reaction which is shown below:
Step1: the first step of the reaction involves the nucleophilic attack. This is the fast step of the mechanism. The nucleophilic attack on the m-chlorobenzaldehyde is shown as:
Step 2: This step involves the hydride transfer. This is the slowest step hence the rate-determining step of the reaction. The hydride transfer is shown as:
