DP Chemistry (last assessment 2024)
Question 19N.2.hl.TZ0.4a(ii)
| Date | November 2019 | Marks available | [Maximum mark: 1] | Reference code | 19N.2.hl.TZ0.4a(ii) |
| Level | hl | Paper | 2 | Time zone | TZ0 |
| Command term | Justify, State | Question number | a(ii) | Adapted from | N/A |
a(ii).
[Maximum mark: 1]
19N.2.hl.TZ0.4a(ii)
A molecule of citric acid, C6H8O7, is shown.
The equation for the first dissociation of citric acid in water is
C6H8O7 (aq) + H2O (l) C6H7O7− (aq) + H3O+ (aq)
(a(ii))
The value of Ka at 298 K for the first dissociation is 5.01 × 10−4.
State, giving a reason, the strength of citric acid.
[1]
Markscheme
weak acid AND partially dissociated
OR
weak acid AND equilibrium lies to left
OR
weak acid AND Ka < 1 ✔
