A chromatography column, packed with silica gel as stationary phase, was used to separate a mixture of compounds consisting of (A) benzanilide, (B) aniline and (C) acetophenone. When the column is elu

Question

A chromatography column, packed with silica gel as stationary phase, was used to separate a mixture of compounds consisting of (A) benzanilide, (B) aniline and (C) acetophenone. When the column is eluted with a mixture of solvents hexane:ethyl acetate (20:80), the sequence of obtained compounds is:

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Step 1: Identify Polarity of Each Compound

| Compound | Functional Group | Polarity |
|---|---|---|
| A — Benzanilide () | Amide (C=O + N-H) | High polarity (H-bond donor + acceptor) |
| B — Aniline () | Primary amine (N-H₂) | Moderate-high polarity (H-bond donor) |
| C — Acetophenone () | Ketone (C=O only) | Moderate polarity (H-bond acceptor, no donor) |

Step 2: Apply Adsorption Rule on Silica Gel

Silica gel is a polar adsorbent. Adsorption order:

Polarity order: Benzanilide (A)  Aniline

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