`CH_(3)CHO and C_(6)H_(5)CH_(2)CHO` can be distinguished chemically by

Options

A. Benedict's test
B. Iodoform test
C. Tollen's test
D. Fehling's test

Explanation

To distinguish between the two aldehydes, CH₃CHO (acetaldehyde) and C₆H₅CH₂CHO (benzaldehyde), we can use the iodoform test. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Compounds**:
- CH₃CHO is acetaldehyde, an aliphatic aldehyde.
- C₆H₅CH₂CHO is benzaldehyde, which is an aromatic aldehyde.

2. **Understand the Iodoform Test**:
- The iodoform test is used to identify methyl ketones or aldehydes that can be oxidized to methyl ketones.
- In this test, the compound is treated with iodine (I₂) in the presence of sodium hydroxide (NaOH).

3. **Perform the Test on Acetaldehyde (CH₃CHO)**:
- When acetaldehyde is treated with I₂ and NaOH, it undergoes a reaction to form iodoform (CHI₃), which is a yellow precipitate.
- The reaction can be summarized as follows:
\[ CH₃CHO + 3 I₂ + 4 NaOH \rightarrow CHI₃ (yellow precipitate) + 3 NaI + 3 H₂O \]

4. **Perform the Test on Benzaldehyde (C₆H₅CH₂CHO)**:
- When benzaldehyde is treated with I₂ and NaOH, no reaction occurs because benzaldehyde does not have a methyl group adjacent to the carbonyl group that can be oxidized to form a methyl ketone.
- Therefore, no yellow precipitate is formed.

5. **Conclusion**:
- The presence of a yellow precipitate indicates the presence of acetaldehyde (CH₃CHO), while the absence of a precipitate indicates benzaldehyde (C₆H₅CH₂CHO).
- Thus, these two aldehydes can be distinguished using the iodoform test.

### Final Answer:
CH₃CHO and C₆H₅CH₂CHO can be distinguished chemically by the iodoform test.