CAIE A Level Chemistry 9701 · Hydroxy compounds
The pKa values of water, ethanol, and phenol at 25°C are 15.7, 16.0, and 10.0 respectively. Compare the relative acidities of these three compounds. Explain the reasons for the differences in terms of the stability of their conjugate bases.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.