CAIE A Level Chemistry 9701 · Equilibria
A buffer solution is made by mixing aqueous ethanoic acid, , with aqueous sodium ethanoate, . Explain how this buffer solution controls the pH when small amounts of a strong acid and of a strong base are added. Include equations in your answer.
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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