DP Chemistry (first assessment 2025)
Question 21N.2.HL.TZ0.c
Date | November 2021 | Marks available | [Maximum mark: 3] | Reference code | 21N.2.HL.TZ0.c |
Level | HL | Paper | 2 | Time zone | TZ0 |
Command term | Label, Sketch | Question number | c | Adapted from | N/A |
c.
[Maximum mark: 3]
21N.2.HL.TZ0.c
Sketch the neutralisation curve obtained and label the equivalence point.
[3]
Markscheme
OR
starts at 1.6 AND finishes at 13.6 ✔
approximately vertical at the correct volume of alkali added ✔
equivalence point labelled AND above pH 7 ✔
Accept any range from 1.1-1.9 AND 13.1-13.9 for M1 or ECF from 11c(i) and 11c(ii).
Award M2 for vertical climb at 28 cm3 OR 15 cm3.
Equivalence point must be labelled for M3.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.1—Proton transfer reactions » Reactivity 3.1.13—pH curves of different combinations of strong and weak monoprotic acids and bases have characteristic shapes and features. Interpret the general shapes of pH curves for all four combinations of strong and weak acids and bases.