Question

TLC analysis of a mixture having 3 components (A, B, C) using silica gel as the stationary phase gave following R_f values; for A = 0.72, B = 0.48, C = 0.20.

Regarding the above observations, which one of the following statements is not correct for column chromatography of the mixture?

• A. A is the most non-polar component
• B. C is the most soluble component in mobile phase
• C. A will be eluted first
• D. C is the most strongly absorbed component

Hint:

R_f = distance moved by compound / distance moved by solvent; higher R_f means less adsorbed on silica, less polar, eluted first.

Answer 1

The Correct Option is B

Step 1: Test each statement using the R_f order A > B > C. Elution order in column chromatography on silica follows decreasing R_f: A first, then B, then C.
Step 2: (A) True: highest R_f means lowest polarity. (C) True: A elutes first. (D) True: C binds strongest to silica.
Step 3: (B) The component that is strongly held on the adsorbent and moves least is the least soluble in the mobile phase, not the most soluble. So (B) is the incorrect statement.
Answer: (B) C is the most soluble component in mobile phase