Which of the following reaction is not correct according to major product

Answer

To determine which of the following reactions is not correct according to the major product, we will analyze each reaction step by step.

### Step 1: Analyze the Kanigero Reaction
The first reaction involves the Kanigero reaction, where one aldehyde is reduced to an alcohol, and another aldehyde is oxidized to an acid (or its ion).

- **Reaction Overview**: In the presence of concentrated NaOH, the aldehyde undergoes reduction and oxidation.
- **Conclusion**: Since the conditions match the Kanigero reaction, this reaction is correct.

**Hint**: Remember that in the Kanigero reaction, one aldehyde gets reduced while another gets oxidized.

### Step 2: Analyze the Second Reaction
The second reaction involves an elimination reaction where an alcohol and heat are present.

- **Reaction Overview**: The presence of a weak leaving group (fluorine) suggests that elimination may not proceed as expected. The base will abstract a hydrogen, forming a conjugate base.
- **Expected Product**: The major product formed is an alkene. However, due to the weak leaving group, the expected alkene may not form correctly.
- **Conclusion**: This reaction is incorrect because the weak leaving group (fluorine) will hinder the formation of the expected major product.

**Hint**: Consider the stability of the leaving group; weak leaving groups can lead to unexpected products.

### Step 3: Analyze the Third Reaction
The third reaction involves a nucleophilic attack by hydroxide on a carbonyl compound.

- **Reaction Overview**: The nucleophile (OH-) attacks the carbonyl carbon, leading to the formation of a carbanion and subsequent protonation to form chloroform.
- **Expected Product**: The reaction proceeds correctly, leading to the formation of chloroform (CHCl3).
- **Conclusion**: This reaction is correct as it follows the expected mechanism.

**Hint**: Nucleophilic attacks on carbonyls often lead to stable products; check the mechanism carefully.

### Final Conclusion
After analyzing all three reactions:
- The first and third reactions are correct according to the major product.
- The second reaction is not correct due to the weak leaving group leading to an unexpected product.

Thus, the answer to the question is that the **second reaction is not correct according to the major product**.