Paper chromatography

2 marks · Normal

State two reasons why the line for the origin is drawn with pencil, not pen, in a paper chromatography experiment.

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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Also accept: Pencil does not dissolve or move with the solvent; Pen ink may dissolve and move in the solvent; Pencil will stay in place; Pen contains dyes that could interfere with results

Common mistakes: Stating pencil is more visible without further explanation

Show mark scheme and worked solution

Marking points

B1 · 1 mark · States that pencil does not dissolve or travel with the solvent or does not interfere with chromatogram

B2 · 1 mark · States that pen ink may dissolve/move up paper/interfere with or contaminate the sample(s)

Worked solution

1. Pencil does not dissolve in the solvent or move with the solvent front.

2. Pen ink may dissolve in the solvent and could move up the paper, interfering with the chromatogram.