To determine the exact volume of dilute nitric acid required to neutralise 25.0 cm3 of potassium hydroxide solution, a student performs a titration. Table 1 shows the results of the four titrations carried out.
Table 1
| Titration 1 (Rough) | Titration 2 | Titration 3 | Titration 4 | |
|---|---|---|---|---|
| Final burette reading / cm3\text{cm}^3cm3 | 25.30 | 25.10 | 24.10 | 26.15 |
| Initial burette reading / cm3\text{cm}^3cm3 | 0.50 | 1.20 | 0.00 | 2.15 |
| Volume of acid used / cm3\text{cm}^3cm3 | 24.80 | 23.90 | 24.10 | 24.00 |
In this analysis, concordant results are defined as volumes of acid used that are within 0.20 cm3 of each other.
Calculate the mean volume of nitric acid required, using only the concordant results.
276 exam-style questions on Edexcel GCSE Chemistry 4.1 Acids, covering 4.1.1 Acids, alkalis and the pH scale, 4.1.2 Hydrogen ion concentration and pH, 4.1.3 Dilute and concentrated, weak and strong acids, 4.1.4 Bases, alkalis and the reactions of acids, 4.1.5 Chemical tests for hydrogen and carbon dioxide, 4.1.6 Neutralisation as a reaction of acids with bases, 4.1.7 Preparing soluble salts, and 4.1.8 Solubility rules and preparing insoluble salts. Each one has a worked solution and a mark scheme showing where the marks go.