A student titrated 25.0 cm325.0\text{ cm}^325.0 cm3 portions of an ethanedioic acid (H2C2O4\text{H}_2\text{C}_2\text{O}_4H2C2O4) solution of unknown concentration with a 0.125 mol/dm30.125\text{ mol/dm}^30.125 mol/dm3 sodium hydroxide (NaOH\text{NaOH}NaOH) solution.
The student's results are shown in the table below:
| Titration | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Volume of sodium hydroxide solution added (in cm3\text{cm}^3cm3) | 24.70 | 23.85 | 24.15 | 23.90 | 23.80 |
The equation for the reaction is:
2NaOH+H2C2O4→Na2C2O4+2H2O 2\text{NaOH} + \text{H}_2\text{C}_2\text{O}_4 \rightarrow \text{Na}_2\text{C}_2\text{O}_4 + 2\text{H}_2\text{O} 2NaOH+H2C2O4→Na2C2O4+2H2OCalculate the concentration of the ethanedioic acid in mol/dm3\text{mol/dm}^3mol/dm3.
Use only the student's concordant results. Concordant results are those within 0.10 cm30.10\text{ cm}^30.10 cm3 of each other.
40 exam-style questions on AQA GCSE Chemistry 4.2 Reactions of acids, covering 4.2.1 Reactions of acids with metals, 4.2.2 Neutralisation of acids and salt production, 4.2.3 Soluble salts, 4.2.4 The pH scale and neutralisation, 4.2.5 Titrations, and 4.2.6 Strong and weak acids (HT only). Each one has a worked solution and a mark scheme showing where the marks go.