Which of the following reaction(s) is/are wrong?

Options

A. a.
B. b.
C. c.
D. d.

Explanation

To determine which of the reactions are wrong, we will analyze each reaction step by step.

### Step 1: Analyze Reaction A
1. **Starting Material**: A phenyl ring with an ethyl group (–CH2CH3) and a bromine atom (–Br) in the ortho position.
2. **Reagent**: Magnesium (Mg) in ether.
3. **Reaction**: The bromine reacts with magnesium to form a Grignard reagent (C6H5CH2CH3MgBr).
4. **Outcome**: The ethyl group remains intact, and the Grignard reagent is formed correctly.

**Conclusion for Reaction A**: This reaction is correct.

### Step 2: Analyze Reaction B
1. **Starting Material**: The same phenyl ring with an ethyl group and bromine.
2. **Reagent**: Grignard reagent (from Reaction A) treated with CO2 followed by H3O+.
3. **Reaction**: The Grignard reagent reacts with CO2 to form benzoic acid (C6H5COOH) while the ethyl group remains unchanged.
4. **Next Step**: KMnO4 in the presence of H+ is used, which oxidizes the ethyl group to a carboxylic acid (–COOH).
5. **Outcome**: The final product should be phthalic acid (C6H4(COOH)2) after heating, which forms an anhydride.

**Conclusion for Reaction B**: The formation of an anhydride from phthalic acid is not correctly represented in the steps provided, making this reaction wrong.

### Step 3: Analyze Reaction C
1. **Starting Material**: The same phenyl ring with an ethyl group.
2. **Reagent**: Chromyl chloride (CrO2Cl2) in CCl4.
3. **Reaction**: This is an ethyl reaction that should yield an aldehyde.
4. **Outcome**: The expected product should maintain the same number of carbons as the starting material. However, the reaction indicates a loss of one carbon atom.

**Conclusion for Reaction C**: The product has one less carbon than the reactant, indicating that this reaction is also wrong.

### Step 4: Analyze Reaction D
1. **Starting Material**: The same phenyl ring with an ethyl group.
2. **Reagent**: KMnO4 in H+.
3. **Reaction**: This reaction oxidizes the side chain to benzoic acid.
4. **Outcome**: The product is correctly formed as benzoic acid.

**Conclusion for Reaction D**: This reaction is correct.

### Final Conclusion
- **Wrong Reactions**: B and C
- **Correct Reactions**: A and D

### Summary of Wrong Reactions:
- **B**: Incorrect due to the misrepresentation of anhydride formation.
- **C**: Incorrect due to loss of carbon in the product.

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