Consider the following reaction.
`underset(CHO) underset(|) (CHO) + OH^(-) to underset(CH_(2)OH) underset(|)(COO^(-))`
Select the incorrect statement.

Options

A. It is not a disproportionation reaction
B. It is intramolecular redoc reaction
C. `OH^(-)` is a reducing as sell as oxidising agent
D. `{:(CHO),(|),(CHO):}` is a reducing as well as oxidising agent

Answer

To solve the question regarding the reaction of CHO (aldehyde) with OH⁻, let's analyze the statements step by step to identify the incorrect one.

### Step 1: Understand the Reaction
The given reaction is:
\[ \text{CHO} + \text{OH}^- \rightarrow \text{COO}^- + \text{CH}_2\text{OH} \]

In this reaction:
- One CHO (aldehyde) is oxidized to COO⁻ (carboxylate ion).
- The other CHO is reduced to CH₂OH (alcohol).

### Step 2: Check for Disproportionation
A disproportionation reaction is one where a single substance is both oxidized and reduced to form two different products. In this case, we have:
- One CHO is oxidized (to COO⁻).
- One CHO is reduced (to CH₂OH).

Since both processes involve different products from the same reactant, this is **not** a disproportionation reaction.

**Conclusion**: The statement claiming it is a disproportionation reaction is **incorrect**.

### Step 3: Identify Intramolecular Redox Reaction
An intramolecular redox reaction involves the same molecule undergoing both oxidation and reduction. Here, the same molecule (CHO) is undergoing both processes, thus it qualifies as an intramolecular redox reaction.

**Conclusion**: This statement is **correct**.

### Step 4: Analyze the Role of OH⁻
The statement claims that OH⁻ is both a reducing and oxidizing agent. However, in this reaction, it is the CHO that acts as both a reducing and oxidizing agent, while OH⁻ primarily serves as a base.

**Conclusion**: This statement is **incorrect**.

### Step 5: Check CHO's Role
The statement that CHO is both a reducing and oxidizing agent is true. In this reaction, CHO is oxidized to COO⁻ and reduced to CH₂OH.

**Conclusion**: This statement is **correct**.

### Final Answer
The incorrect statement among the options provided is that "OH⁻ is a reducing as well as oxidizing agent."

### Summary of Steps
1. **Understand the reaction**: Identify the products formed from CHO.
2. **Check for disproportionation**: Determine if the same substance is both oxidized and reduced.
3. **Identify intramolecular redox**: Confirm if the same molecule is involved in both processes.
4. **Analyze the role of OH⁻**: Determine if OH⁻ acts as a reducing or oxidizing agent.
5. **Check CHO's role**: Confirm if CHO can act as both a reducing and oxidizing agent.