Paper 3 Advanced Practical Skills 1
9701/31 · October/November 2025
EXAM CONDITIONS
Your bench has been set out for 9701/31.
Everything on this paper is what the confidential instructions told the technician to put in front of you — the same solutions, the same glassware, labelled exactly as the candidate sees them. You are not told what B, C, D, E or F are. That's the point.
3 tasks · 19 questions · 40 marks
Redox titration: ethanedioic acid vs manganate(VII)
Heat FA 1 with dilute sulfuric acid to about 70°C, then titrate against acidified potassium manganate(VII) to a self-indicating pale pink end-point, and use the stoichiometry to find x in (COOH)₂·xH₂O.
Thermal decomposition of hydrated zinc sulfate
Heat FA 4 in a crucible to constant mass, then use the mass lost as water of crystallisation to find y in ZnSO₄·yH₂O.
Qualitative analysis: a mislabelled salt and three manganese oxidation states
Devise your own tests for zinc, sulfate and water of crystallisation on FA 5, then heat solid FA 6 and compare it against FA 7, FA 8 and FA 9 to work out what links them.