Question

Two compounds I and II are eluted by column chromatography (adsorption of I > II). Which one of following is a correct statement ?

• A. I moves faster and has higher $R_f$ value than $II$
• B. II moves faster and has higher $R_f$ value than $I$
• C. I moves slower and has higher $R_f$ value than $II$
• D. II moves slower and has higher $R_f$ value than $I$

Answer 1

Answer: (B)

II moves faster and has higher $R_f$ value than $I$

Answer 2

The $R_{r}$ value is the distance travelled by the substance divided by the distance travelled by the solvent front. As $I$ adsorbs more than II, therefore, II will move faster and will have higher $R_{f}$ than 1 .