Chemistry · Oct / Nov 2017 · Paper 12 · Question 5

A chemist wishes to separate and identify a mixture of substances using paper chromatography. The diagram shows the apparatus used. The solvent is water. [diagram of chromatography apparatus with solvent] The solvent front is allowed to reach the top of the paper before the chemist removes the paper from the solvent. Which problem does this cause?

1. AThis causes the spot nearest the bottom of the paper to catch up with the spot above it.
2. BThis makes it impossible to calculate Rf values.
3. CThis makes it impossible to use a locating agent.
4. DThis results in a safety hazard caused by solvent fumes.

As printed in the paper