Study the following sequence of reaction and identify the product (Y).
`CH_(3)CHO +HCHO overset("dil."NaOH)underset("heat") to X overset(HCN) underset(H_(3)O^(+)) to Y`

Options

A. `CH_(2)=CH-underset(OH)underset(|)(CH)-COOH`
B. `CH_(3)-overset(CN)overset(|)underset(OH)underset(|)C-COOH`
C. `CH_(3)CH_(2)-underset(OH) underset(|)CH-COOH`
D. `CH_(2)=CH-underset(CN)underset(|)(CH)-COOH`

Explanation

To identify the product (Y) from the given sequence of reactions, we will analyze each step carefully.

### Step 1: Identify the Reactants
The reactants are:
- Acetaldehyde (CH₃CHO)
- Formaldehyde (HCHO)

### Step 2: Reaction with Dilute NaOH and Heat
When acetaldehyde reacts with formaldehyde in the presence of dilute NaOH and heat, an aldol condensation reaction occurs.

1. **Formation of Enolate Ion**:
- Acetaldehyde has an alpha hydrogen that can be abstracted by NaOH, forming an enolate ion.
- The enolate ion acts as a nucleophile.

2. **Nucleophilic Addition**:
- The enolate ion attacks the carbonyl carbon of formaldehyde, leading to the formation of a β-hydroxy aldehyde (an aldol).

The structure of the intermediate product (X) formed is:
- **Product X**: 3-hydroxybutanal (CH₂(OH)CH₂CHO)

### Step 3: Reaction with HCN and Hydrolysis
Next, product X undergoes a reaction with hydrogen cyanide (HCN) followed by hydrolysis.

1. **Nucleophilic Addition of HCN**:
- The carbonyl carbon of the β-hydroxy aldehyde (X) is electrophilic and can react with HCN.
- This results in the formation of a cyanohydrin.

2. **Hydrolysis**:
- The cyanohydrin can be hydrolyzed to form an amide and then further hydrolyzed to yield a carboxylic acid.

The final product (Y) after hydrolysis is:
- **Product Y**: 3-hydroxybutanoic acid (CH₂(OH)CH₂COOH)

### Final Answer
The product (Y) formed from the given sequence of reactions is **3-hydroxybutanoic acid**.

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