CAIE A Level Chemistry 9701 · Equilibria
A student measures the pH of separate 0.1 mol dm⁻³ solutions of hydrochloric acid, , and ethanoic acid, , using a pH meter. The pH of the hydrochloric acid is 1.0, while the pH of the ethanoic acid is 2.9.
Explain why the pH of the ethanoic acid solution is higher than the pH of the hydrochloric acid solution.
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.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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