CAIE A Level Chemistry 9701 · Nitrogen compounds
The relative basicities of three nitrogen-containing compounds can be compared by measuring the pH of equimolar aqueous solutions. The results are shown.
| Compound | pH of 0.1 mol dm⁻³ aqueous solution |
|---|---|
| aqueous ammonia | 11.1 |
| ethylamine | 11.3 |
| phenylamine | 8.8 |
Compare the basicities of aqueous ammonia, ethylamine and phenylamine, and explain the differences in terms of the availability of the lone pair on the nitrogen atom.
7 marks, so the mark scheme is looking for about 7 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.
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