Which statement is true about benzaldehyde

Options

A. It does not react with Tollen’s reagent
B. It does not react with Fehling’s solution
C. It does not react with HCN
D. It does not react with `"NaHSO"_(3)`

Answer

To determine which statement is true about benzaldehyde, we will analyze the properties and reactions of benzaldehyde with various reagents.

### Step-by-Step Solution:

1. **Understanding Benzaldehyde Structure**:
- Benzaldehyde is an aromatic aldehyde with the chemical formula C₇H₆O. Its structure consists of a benzene ring (C₆H₅) attached to a formyl group (CHO).

**Hint**: Remember that the functional group of an aldehyde is -CHO, which is crucial for its reactivity.

2. **Reactivity with Tollens' Reagent**:
- Tollens' reagent is an ammoniacal silver nitrate solution that acts as an oxidizing agent. It reacts with both aliphatic and aromatic aldehydes.
- Since benzaldehyde is an aromatic aldehyde, it will react with Tollens' reagent, producing a precipitate of silver.

**Hint**: Tollens' reagent is used to test for aldehydes; if it reacts, the compound is likely an aldehyde.

3. **Reactivity with Fehling's Solution**:
- Fehling's solution is used to test for reducing sugars and aliphatic aldehydes. It does not react with aromatic aldehydes like benzaldehyde.
- Therefore, benzaldehyde will not react with Fehling's solution.

**Hint**: Remember that Fehling's solution is specific to aliphatic aldehydes and does not react with aromatic ones.

4. **Reactivity with HCN (Hydrogen Cyanide)**:
- Benzaldehyde can react with HCN through a nucleophilic addition reaction. The cyanide ion (CN⁻) acts as a nucleophile and attacks the electrophilic carbon of the carbonyl group (C=O).
- Therefore, the statement that benzaldehyde does not react with HCN is false.

**Hint**: Nucleophilic addition reactions are common for carbonyl compounds, including aldehydes.

5. **Reactivity with Sodium Bisulfite (NaHSO₃)**:
- Benzaldehyde can react with sodium bisulfite to form a bisulfite adduct. The nucleophilic part (HSO₃⁻) attacks the carbonyl carbon, leading to the formation of a stable adduct.
- Thus, the statement that benzaldehyde does not react with NaHSO₃ is also false.

**Hint**: Sodium bisulfite is often used to form adducts with aldehydes and ketones.

### Conclusion:
Based on the analysis, the true statement about benzaldehyde is that it does not react with Fehling's solution.

### Final Answer:
**The true statement about benzaldehyde is that it does not react with Fehling's solution.**