Question 22N.2.sl.TZ0.4a.iii
| Date | November 2022 | Marks available | [Maximum mark: 2] | Reference code | 22N.2.sl.TZ0.4a.iii |
| Level | sl | Paper | 2 | Time zone | TZ0 |
| Command term | Explain | Question number | a.iii | Adapted from | N/A |
An organic compound, A, reacts with ethanoic acid to produce B using concentrated sulfuric acid as a catalyst.
Explain, with reference to intermolecular forces, why B is more volatile than A.
[2]
A has hydrogen bonding/bonds «and dipole-dipole and London/dispersion forces» AND B has dipole-dipole «and London/dispersion forces»
OR
A has hydrogen bonding/bonds AND B does not ✔
intermolecular forces are weaker in B
OR
hydrogen bonding/bonds stronger «than dipole-dipole» ✔
This question about intermolecular forces discriminated well between high-achieving and low-achieving candidates. Stronger candidates showed excellent understanding of the types of intermolecular forces found between the molecules of each compound and how they compared in strength. They gave more detail than the markscheme required. The average mark on the question was 0.8 out of 2. 21% of the candidates left the question blank. Error carried forward was applied whenever it was possible based on the answer in (a)(i).
