Question

Iodoform test can differentiate :

• A. Anisole and Acetone
• B. Acetic acid and Aniline
• C. Ethanol and Acetone
• D. Methanol and benzoic acid

Hint:

The Iodoform test is specific for compounds containing either $R-\text{CO}-\text{CH}_3$ (methyl ketone) or $R-\text{CH}(\text{OH})-\text{CH}_3$ (methyl carbinol). $\text{CH}_3\text{OH}$ and $\text{CH}_3\text{CHO}$ are special cases that also test positive.

Answer 1

The Correct Option is A

The iodoform test is a qualitative test in organic chemistry used to identify the presence of certain functional groups. It specifically helps to identify compounds that contain the CH₃CO group (methyl ketones) or those that can be oxidized to methyl ketones.

Let's evaluate the options one by one to determine which pair can be distinguished by the iodoform test: 

1. Anisole and Acetone:
   • Anisole (C₆H₅OCH₃) does not contain the CH₃CO group and therefore does not give a positive iodoform test.
   • Acetone (CH₃COCH₃) is a methyl ketone and will give a positive iodoform test.
   • Thus, the iodoform test can differentiate between Anisole and Acetone.
2. Acetic acid and Aniline:
   • Acetic acid (CH₃COOH) can be converted into a methyl ketone, but generally, it does not respond to the iodoform test at ordinary conditions. It is not a direct test subject like Acetone.
   • Aniline (C₆H₅NH₂) does not contain the CH₃CO group and will not give the iodoform test.
   • Therefore, the iodoform test cannot differentiate between Acetic Acid and Aniline directly.
3. Ethanol and Acetone:
   • Ethanol (CH₃CH₂OH) can be oxidized to acetaldehyde (CH₃CHO) which can give the iodoform test. However, ethanol itself does not give a direct iodoform reaction like Acetone.
   • Acetone, as already explained, gives a positive iodoform test because it is a methyl ketone.
   • This makes the differentiation possible, but not as distinctly as with Anisole and Acetone.
4. Methanol and Benzoic Acid:
   • Methanol (CH₃OH) does not get oxidized to a methyl ketone and hence does not give the iodoform test.
   • Benzoic acid (C₆H₅COOH) also does not contain the CH₃CO group and does not give the iodoform test.
   • Thus, the iodoform test cannot differentiate between them.

Therefore, the correct answer is that the iodoform test can differentiate Anisole and Acetone.