DP Chemistry (last assessment 2024)
Question 19M.1.hl.TZ1.27
Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.1.hl.TZ1.27 |
Level | hl | Paper | 1 | Time zone | TZ1 |
Command term | Question number | 27 | Adapted from | N/A |
27.
[Maximum mark: 1]
19M.1.hl.TZ1.27
Which has the strongest conjugate base?
A. HCOOH (Ka = 1.8 × 10−4)
B. HNO2 (Ka = 7.2 × 10−4)
C. HCN (Ka = 6.2 × 10−10)
D. HIO3 (Ka = 1.7 × 10−1)
[1]
Markscheme
C
Examiners report
Strength of conjugate bases appeared to be another good discriminator, with higher scoring candidates performing better.