Acetaldehyde on treatment with hydrogen cyanide followed by hydrolysis gives:

Options

A. formic acid
B. acetic acid
C. lactic acid
D. tartaric acid

Answer

To solve the question of what acetaldehyde produces when treated with hydrogen cyanide followed by hydrolysis, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactant is acetaldehyde, which has the chemical formula CH₃CHO.

2. **Reaction with Hydrogen Cyanide**:
- When acetaldehyde reacts with hydrogen cyanide (HCN), it undergoes a nucleophilic addition reaction. The cyanide ion (CN⁻) acts as a nucleophile and attacks the carbonyl carbon of acetaldehyde.
- This reaction produces a cyanohydrin. The structure of the cyanohydrin formed is CH₃CHOHCN, which can be written as CH₃C(OH)(CN)H.

3. **Hydrolysis of the Cyanohydrin**:
- The cyanohydrin formed can undergo hydrolysis when treated with water in the presence of an acid (like dilute HCl).
- During hydrolysis, the cyanohydrin will convert into a carboxylic acid and ammonia. The hydroxyl group (OH) and the carboxyl group (COOH) will be formed from the hydrolysis of the cyanide group (CN).

4. **Formation of Lactic Acid**:
- The hydrolysis of the cyanohydrin leads to the formation of lactic acid (C₃H₆O₃). The reaction can be summarized as:
- CH₃C(OH)(CN)H + H₂O → CH₃C(OH)(COOH) + NH₄⁺
- The product formed is lactic acid, which has the structure CH₃C(OH)(COOH).

5. **Conclusion**:
- Therefore, when acetaldehyde is treated with hydrogen cyanide followed by hydrolysis, the final product is lactic acid.

### Final Answer:
The correct answer is **lactic acid (Option 3)**.

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