Question

Given below are two statements:

Statement I: The nucleophilic addition of sodium hydrogen sulphite to an aldehyde or a ketone involves proton transfer to form a stable ion.

Statement II: The nuceophilic addition of hydrogen cyanide to an aldehyde or a ketone yields amine as final product.

In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Statement I is false but statement II is true
• B. Statement I is true but statement II is false
• C. Both Statement I and Statement II are true
• D. Both Statement I and Statement II are false

Answer 1

The correct option is B Statement I is true but statement II is false

Sodium hydrogensulphite $\left(NaHS{O}_3\right)$adds to aldehydes and ketones to form the addition products. The hydrogensulphite addition compound is water soluble and can be converted back to the original carbonyl compound by treating it with dilute mineral acid or alkali.

Hence, option (a) is correct.

Mechanism of addition of $NaHS{O}_3$ involves 2 steps.
Step-1: Nucleophilic attack on ​carbonyl carbon:
Step-2: Formation of an adduct