| Date | May 2009 | Marks available | 1 | Reference code | 09M.1.hl.TZ2.29 |
| Level | HL | Paper | 1 | Time zone | TZ2 |
| Command term | Deduce | Question number | 29 | Adapted from | N/A |
Question
At the same concentration, which acid would have the lowest pH?
\(\begin{array}{*{20}{l}} {{\text{A.}}}&{{\text{HN}}{{\text{O}}_{\text{2}}}}&{{K_{\text{a}}} = 5.6 \times {{10}^{ - 4}}{\text{ mol}}\,{\text{d}}{{\text{m}}^{ - 3}}} \\ {{\text{B.}}}&{{\text{HF}}}&{{K_{\text{a}}} = 6.8 \times {{10}^{ - 4}}{\text{ mol}}\,{\text{d}}{{\text{m}}^{ - 3}}} \\ {{\text{C.}}}&{{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{COOH}}}&{{K_{\text{a}}} = 6.3 \times {{10}^{ - 5}}{\text{ mol}}\,{\text{d}}{{\text{m}}^{ - 3}}} \\ {{\text{D.}}}&{{\text{HCN}}}&{{K_{\text{a}}} = 4.9 \times {{10}^{ - 10}}{\text{ mol}}\,{\text{d}}{{\text{m}}^{ - 3}}} \end{array}\)
Markscheme
B
Examiners report
[N/A]
Syllabus sections
Additional higher level (AHL) » Topic 18: Acids and bases » 18.2 Calculations involving acids and bases
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