DP Chemistry (last assessment 2024)
Question 23M.2.SL.TZ2.5a
| Date | May 2023 | Marks available | [Maximum mark: 2] | Reference code | 23M.2.SL.TZ2.5a |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Calculate | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 2]
23M.2.SL.TZ2.5a
(a)
The concentration of methanoic acid was found by titration with a 0.200 mol dm−3 standard solution of sodium hydroxide, NaOH (aq), using an indicator to determine the end point.
Calculate the pH of the sodium hydroxide solution.
[2]
Markscheme
«[OH−] = 0.200 mol dm−3»
ALTERNATIVE 1:
«pOH = −log10(0.200) =» 0.699 ✓
«pH = 14.000 − 0.699 =» 13.301 ✓
ALTERNATIVE 2:
«[H+] = = » 5.00 × 10−14 «mol dm−3» ✓
«pH = −log10(5.00 × 10−14)» = 13.301 ✓
Award [2] for correct final answer.
