O-LevelChemistryAcids, Bases & Salts5070/11 · May/June 2023 · Q391 Mark
A paper chromatography experiment is used to find an Rf value for Fe³⁺(aq). The chromatogram is shown. [Chromatogram showing solvent front, Fe³⁺ spot, starting line, with distances x (spot distance) and y (solvent front distance) marked]. To make the spot containing Fe³⁺(aq) more visible, the paper is sprayed with aqueous sodium hydroxide so that a precipitate of iron(III) hydroxide forms. In the chromatogram, the Rf of Fe³⁺(aq) is given by ......1...... and the colour of the precipitate is ......2...... Which row correctly completes gaps 1 and 2?
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Agap 1: x/y, gap 2: red-brown
Bgap 1: x/y, gap 2: green
Cgap 1: y/x, gap 2: red-brown
Dgap 1: y/x, gap 2: green
✓ Correct answer
A: gap 1: x/y, gap 2: red-brown
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