CAIE A Level Chemistry 9701 · Equilibria
A student measures the pH of two solutions of equal concentration, 0.1 mol dm hydrochloric acid and 0.1 mol dm ethanoic acid. The pH of the hydrochloric acid is 1.0 and the pH of the ethanoic acid is 2.9. Suggest why the pH values are different.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Suggest means: Apply what you know to an unfamiliar situation. There may be more than one acceptable answer. Reason from the principle you have learned to the new context, and say which principle you are using.
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