In the reaction ,
`CH_(3)CHO + HCN rarr A underset(H_(2)O)overset(H^(+))(rarr) B `
The product B is ?

Options

A. `CH_(3)COH(CH_(3))CH(2)COCH_(3)`
B. `CH_(3)C(OH)(CH_(3))CH_(2)COOH`
C. `CH_(3)CH(OH)CO OH`
D. `CH_(3)CH=CHCH_(2)COCH_(3)`

Explanation

To solve the given reaction step by step, let's analyze the reactants and products involved.

### Step 1: Identify the Reactants
The reaction involves:
- **Reactant 1**: Acetaldehyde (CH₃CHO)
- **Reactant 2**: Hydrogen cyanide (HCN)

### Step 2: Nucleophilic Addition Reaction
When acetaldehyde (CH₃CHO) reacts with hydrogen cyanide (HCN), the cyanide ion (CN⁻) acts as a nucleophile. It attacks the electrophilic carbon atom of the carbonyl group (C=O) in acetaldehyde.

- The reaction can be represented as:
\[ CH₃CHO + HCN \rightarrow CH₃C(OH)(CN) \]
This intermediate product is known as a cyanohydrin (A).

### Step 3: Protonation of the Intermediate
In the presence of an acid (H⁺) and water (H₂O), the cyanohydrin undergoes hydrolysis. The hydroxyl group (OH) is formed from the addition of water, and the cyanide group (CN) is converted into a carboxylic acid.

- The reaction can be represented as:
\[ CH₃C(OH)(CN) + H₂O \xrightarrow{H^+} CH₃C(OH)(COOH) + NH₃ \]
Here, the CN group is converted to a carboxylic acid (COOH) and ammonia (NH₃) is released.

### Step 4: Final Product (B)
The final product (B) is:
\[ CH₃C(OH)(COOH) \]
This compound is known as 2-hydroxybutanoic acid or lactic acid.

### Conclusion
Thus, the product B formed after the hydrolysis of the intermediate cyanohydrin is a carboxylic acid with a hydroxyl group.

### Final Answer
The product B is **2-hydroxybutanoic acid (lactic acid)**.

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