Unit 12 · Experimental Techniques and Chemical Analysis

Question Bank

Cambridge IGCSE Chemistry 0620 · 59 questions

Q43Experimental Techniques and Chemical Analysis

How is the Rf value of a spot in paper chromatography calculated?

(a)Distance moved by solvent ÷ distance moved by spot

(b)Distance moved by spot ÷ distance moved by solvent front

(c)Distance moved by spot × distance moved by solvent

(d)Distance from baseline to the top of the paper

Correct answer: (b) Distance moved by spot ÷ distance moved by solvent front

Explanation: Rf = distance travelled by the substance ÷ distance travelled by the solvent front, so it is always less than 1.

Related lesson