The pair of the equimolar compound that would be give a single condensation product when treated with an alkali is

Options

A. `CH_(3)-CHO+CH_(3)CH_(2)CHO`
B.
C.
D. `CH_(3)CHO+HCHO`

Answer

To solve the problem of identifying the pair of equimolar compounds that would yield a single condensation product when treated with an alkali, we will analyze the options systematically.

### Step-by-Step Solution:

1. **Understanding Aldol Condensation**:
Aldol condensation occurs when two carbonyl compounds (aldehydes or ketones) react in the presence of a base to form β-hydroxy aldehydes or ketones, which can further dehydrate to give α,β-unsaturated carbonyl compounds.

2. **Identifying Reactivity**:
- Aldehydes are generally more reactive than ketones in aldol condensation reactions.
- Compounds that can undergo self-condensation will lead to multiple products, while those that do not will lead to a single product.

3. **Analyzing the Given Options**:
- **Option 1**: Acetaldehyde and Propanaldehyde
- Both are aldehydes and can undergo self-condensation, leading to multiple products.
- **Option 2**: Paramethylbenzaldehyde and Acetophenone
- Paramethylbenzaldehyde (an aldehyde) and Acetophenone (a ketone) can react. The aldehyde can react with the ketone, but the ketone cannot self-condense. This will lead to a single product.
- **Option 3**: Benzaldehyde and Acetaldehyde
- Acetaldehyde can self-condense, leading to multiple products.
- **Option 4**: Formaldehyde and Acetaldehyde
- Acetaldehyde can self-condense, leading to multiple products.

4. **Conclusion**:
The only pair that gives a single condensation product is **Paramethylbenzaldehyde and Acetophenone**.

### Final Answer:
The pair of equimolar compounds that would give a single condensation product when treated with an alkali is **Paramethylbenzaldehyde and Acetophenone**.

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