Which of the compounds `HCHO(I),CH_3CH_2CHO(II),CH_3COCH_3(III) and RCOOC_2H_5 (IV)` will give a secondary alcohol on reaction with excess Grignard reagent , followed by hydrolysis ? Select the correct answer using the codes given below

Options

A. II only
B. III only
C. I and IV
D. II and IV

Answer

To determine which of the compounds will give a secondary alcohol upon reaction with excess Grignard reagent followed by hydrolysis, we will analyze each compound step by step.

### Step 1: Analyze Formaldehyde (HCHO)
- **Reaction with Grignard Reagent**:
\[ \text{HCHO} + \text{R-MgX} \rightarrow \text{R-CH}_2\text{OH (after hydrolysis)} \]
- **Product**: The reaction of formaldehyde with a Grignard reagent yields a primary alcohol (R-CH2OH).
- **Conclusion**: Formaldehyde does not give a secondary alcohol.

### Step 2: Analyze Propanal (CH3CH2CHO)
- **Reaction with Grignard Reagent**:
\[ \text{CH}_3\text{CH}_2\text{CHO} + \text{R-MgX} \rightarrow \text{CH}_3\text{CH}_2\text{C(OMgX)R} \]
- **Hydrolysis**:
\[ \text{CH}_3\text{CH}_2\text{C(OMgX)R} + \text{H}_2\text{O} \rightarrow \text{CH}_3\text{CH}_2\text{C(OH)(R)H} \]
- **Product**: This results in a secondary alcohol (CH3CH2C(OH)(R)H).
- **Conclusion**: Propanal gives a secondary alcohol.

### Step 3: Analyze Acetone (CH3COCH3)
- **Reaction with Grignard Reagent**:
\[ \text{CH}_3\text{COCH}_3 + \text{R-MgX} \rightarrow \text{CH}_3\text{C(OMgX)(R)}\text{CH}_3 \]
- **Hydrolysis**:
\[ \text{CH}_3\text{C(OMgX)(R)}\text{CH}_3 + \text{H}_2\text{O} \rightarrow \text{CH}_3\text{C(OH)(R)}\text{CH}_3 \]
- **Product**: This results in a tertiary alcohol (CH3C(OH)(R)CH3).
- **Conclusion**: Acetone does not give a secondary alcohol.

### Step 4: Analyze Ester (RCOOC2H5)
- **Reaction with Grignard Reagent**:
\[ \text{RCOOC}_2\text{H}_5 + 2 \text{R-MgX} \rightarrow \text{RCO-MgX} + \text{C}_2\text{H}_5\text{OMgX} \]
- **Hydrolysis**:
\[ \text{RCO-MgX} + \text{C}_2\text{H}_5\text{OMgX} + \text{H}_2\text{O} \rightarrow \text{RCOOH} + \text{C}_2\text{H}_5\text{OH} + \text{R-OH} \]
- **Product**: This results in a tertiary alcohol.
- **Conclusion**: The ester does not give a secondary alcohol.

### Final Conclusion:
The only compound that gives a secondary alcohol upon reaction with excess Grignard reagent followed by hydrolysis is **Propanal (CH3CH2CHO)**.

### Correct Answer:
**Propanal (II)** is the only compound that gives a secondary alcohol.