Give the mechanism of cyanohydrin formation when carbonyl compounds react with HCN in the presence of alkali.

Explanation

### Step-by-Step Text Solution for the Mechanism of Cyanohydrin Formation

1. **Introduction to the Reaction**:
- Carbonyl compounds, such as aldehydes and ketones, react with hydrogen cyanide (HCN) to form cyanohydrins. This reaction is significantly accelerated in the presence of a base.

2. **Base Catalysis**:
- In the presence of a base, the base abstracts a proton (H⁺) from HCN. This results in the formation of a cyanide ion (CN⁻) and a water molecule (H₂O).
- **Reaction**:
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