Which of the compounds `HCHO(I),CH_3CH_2CHO(II),CH_3COCH_3(III) and HCOOC_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 Compound I (HCHO)
- **Structure**: HCHO (formaldehyde) has the structure H2C=O.
- **Reaction with Grignard Reagent**: When HCHO reacts with a Grignard reagent (R-MgX), the nucleophile (R-) attacks the carbonyl carbon, leading to the formation of an alkoxide intermediate.
- **Hydrolysis**: Upon hydrolysis, this intermediate will yield a primary alcohol (RCH2OH).
- **Conclusion**: HCHO gives a primary alcohol, not a secondary alcohol.

### Step 2: Analyze Compound II (CH3CH2CHO)
- **Structure**: CH3CH2CHO (propionaldehyde) has the structure CH3CH2C=O.
- **Reaction with Grignard Reagent**: The Grignard reagent will attack the carbonyl carbon, forming an alkoxide.
- **Hydrolysis**: Hydrolysis of this alkoxide will yield a secondary alcohol (RCH(OH)R').
- **Conclusion**: CH3CH2CHO gives a secondary alcohol.

### Step 3: Analyze Compound III (CH3COCH3)
- **Structure**: CH3COCH3 (acetone) has the structure CH3C(=O)CH3.
- **Reaction with Grignard Reagent**: The Grignard reagent will attack the carbonyl carbon, forming a tertiary alkoxide.
- **Hydrolysis**: Hydrolysis of this alkoxide results in a tertiary alcohol (R3C(OH)).
- **Conclusion**: CH3COCH3 gives a tertiary alcohol, not a secondary alcohol.

### Step 4: Analyze Compound IV (HCOOC2H5)
- **Structure**: HCOOC2H5 (ethyl formate) has the structure HCOO-C2H5.
- **Reaction with Grignard Reagent**: The Grignard reagent will attack the carbonyl carbon of the ester, forming an alkoxide.
- **Hydrolysis**: Upon hydrolysis, this will yield a secondary alcohol (RCH(OH)R').
- **Conclusion**: HCOOC2H5 gives a secondary alcohol.

### Final Conclusion:
The compounds that yield a secondary alcohol upon reaction with excess Grignard reagent followed by hydrolysis are:
- Compound II (CH3CH2CHO)
- Compound IV (HCOOC2H5)

### Answer:
The correct options are II and IV.

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