Benzoic acid can prepared by reacting phenyl magnesium bromide with

Options

A. N, N - dimethylformamide
B. carbon dioxide
C. formaldehyde
D. ethyl chloroformate

Answer

To solve the question of how benzoic acid can be prepared by reacting phenyl magnesium bromide, we will analyze the given options step by step.

### Step 1: Understanding the Reactants
- **Phenyl magnesium bromide (C6H5MgBr)** is a Grignard reagent. Grignard reagents are known for their strong nucleophilic properties.
- We need to identify which of the given reactants can react with phenyl magnesium bromide to form benzoic acid.

### Step 2: Analyzing the Options
1. **N,N-Dimethylformamide (DMF)**:
- When phenyl magnesium bromide reacts with DMF, it forms an addition product but does not yield benzoic acid. Instead, it leads to a different compound.

2. **Carbon Dioxide (CO2)**:
- Grignard reagents react with carbon dioxide to form carboxylic acids. The reaction proceeds as follows:
- C6H5MgBr + CO2 → C6H5C(=O)O−MgBr (carboxylate salt)
- Upon hydrolysis, this salt converts to benzoic acid (C6H5COOH).
- Therefore, this option can produce benzoic acid.

3. **Formaldehyde (HCHO)**:
- The reaction of phenyl magnesium bromide with formaldehyde results in the formation of benzyl alcohol, not benzoic acid.
- C6H5MgBr + HCHO → C6H5CH2OH (benzyl alcohol) upon hydrolysis.

4. **Ethyl Chloroformate (C2H5OCOCl)**:
- This reaction also does not yield benzoic acid. Instead, it leads to the formation of an ester or acyl chloride.
- C6H5MgBr + C2H5OCOCl → C6H5C(=O)O−C2H5 (an ester) upon hydrolysis.

### Step 3: Conclusion
- Among the given options, only the reaction with carbon dioxide leads to the formation of benzoic acid.
- Therefore, the correct answer is **carbon dioxide**.

### Final Answer
Benzoic acid can be prepared by reacting phenyl magnesium bromide with **carbon dioxide**.

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