DP Chemistry (last assessment 2024)
Question 21N.2.hl.TZ0.3b(ii)
| Date | November 2021 | Marks available | [Maximum mark: 3] | Reference code | 21N.2.hl.TZ0.3b(ii) |
| Level | hl | Paper | 2 | Time zone | TZ0 |
| Command term | Outline | Question number | b(ii) | Adapted from | N/A |
b(ii).
[Maximum mark: 3]
21N.2.hl.TZ0.3b(ii)
White phosphorus is an allotrope of phosphorus and exists as P4.
(b(ii))
Outline the reason why PCl5 is a non-polar molecule, while PCl4F is polar.
[3]
Markscheme
PCl5 is non-polar:
symmetrical
OR
dipoles cancel ✔
PCl4F is polar:
P–Cl has a different bond polarity than P–F ✔
non-symmetrical «dipoles»
OR
dipoles do not cancel ✔
Accept F more electronegative than/different electronegativity to Cl for M2.