Which of the following will form two isomers with semi carbazide

Options

A. Benzaldehyde
B. Acetone
C. Benzoquione
D. Benzophenone

Explanation

To determine which of the given carbonyl compounds will form two isomers with semicarbazide, we need to analyze the structure of each compound and how they react with semicarbazide.

### Step-by-Step Solution:

1. **Understanding Semicarbazide Reaction**:
Semicarbazide (NH2-CO-NH-NH2) reacts with carbonyl compounds (aldehydes and ketones) to form semicarbazones. The reaction involves the nucleophilic attack of the amine group on the carbonyl carbon, leading to the formation of a C=N bond and the elimination of water.

**Hint**: Look for the presence of different substituents on the carbonyl carbon to form isomers.

2. **Identifying the Carbonyl Compounds**:
The options provided are:
- Benzaldehyde (C6H5CHO)
- Acetone (CH3COCH3)
- Benzophenone (C6H5COC6H5)
- Benzoquinone (C6H4O2)

3. **Analyzing Benzaldehyde**:
- Benzaldehyde has the structure C6H5CHO, where the carbonyl carbon is bonded to a phenyl group (C6H5) and a hydrogen atom (H).
- This means there are two different substituents (C6H5 and H) on the carbonyl carbon, allowing for the formation of two isomers (cis and trans) when reacting with semicarbazide.

**Hint**: Different substituents lead to the possibility of isomer formation.

4. **Analyzing Acetone**:
- Acetone has the structure CH3COCH3, where both substituents on the carbonyl carbon are methyl groups (CH3).
- Since both substituents are the same, acetone cannot form two distinct isomers.

**Hint**: Identical substituents do not allow for isomer formation.

5. **Analyzing Benzophenone**:
- Benzophenone has the structure C6H5COC6H5, where both substituents on the carbonyl carbon are phenyl groups (C6H5).
- Similar to acetone, since both substituents are the same, benzophenone cannot form two distinct isomers.

**Hint**: Look for unique substituents to determine isomer formation.

6. **Analyzing Benzoquinone**:
- Benzoquinone has the structure C6H4O2, which can be viewed as having similar substituents on the carbonyl groups.
- Since the substituents are not different (both are part of the aromatic ring), it cannot form two distinct isomers.

**Hint**: The structure of the compound is crucial in determining isomer formation.

7. **Conclusion**:
After analyzing all options, only **Benzaldehyde** can form two isomers with semicarbazide due to having two different substituents on the carbonyl carbon.

### Final Answer:
The correct option is **Benzaldehyde**.