| Date | May 2011 | Marks available | 1 | Reference code | 11M.1.hl.TZ1.29 |
| Level | HL | Paper | 1 | Time zone | TZ1 |
| Command term | Deduce | Question number | 29 | Adapted from | N/A |
Question
Which compounds can be mixed together as solutions of equal volume and concentration to form a buffer solution?
A. Nitric acid and potassium hydroxide
B. Nitric acid and potassium nitrate
C. Propanoic acid and potassium hydroxide
D. Propanoic acid and potassium propanoate
Markscheme
D
Examiners report
One G2 stated that the naming of carboxylic acids was not covered. However, according to AS 10.1.10, candidates should know how to apply IUPAC rules to name carboxylic acids up to six carbon atoms. Hence, it would be expected that candidates would know the structure of propanoic acid to subsequently answer this question on buffer solutions. The question was however the second most difficult question on the paper, with only 43.79% of candidates getting the correct answer.
