The most reactive compound towards formation of cyanohydrin on treatment with KCN followed by acidification is

Options

A. benzaldehyde
B. p-nitrobenzaldehyde
C. phenylacetaldehyde
D. p-hydroxybenzaldehyde

Explanation

To determine the most reactive compound towards the formation of cyanohydrin when treated with KCN followed by acidification, we need to analyze the reactivity of different carbonyl compounds (aldehydes and ketones) based on the stability of the carbonyl carbon.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- When KCN is added to a carbonyl compound (aldehyde or ketone), the cyanide ion (CN⁻) acts as a nucleophile and attacks the carbonyl carbon, which has a partial positive charge due to the electronegativity of oxygen.
- The reaction leads to the formation of a cyanohydrin (RC(OH)(CN)) after acidification.

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