A student carries out a titration to determine the concentration of sodium hydroxide (NaOH\text{NaOH}NaOH) in a commercial drain cleaner.
First, the student pipettes 10.0 cm3 of the commercial drain cleaner into a 250.0 cm3 volumetric flask and dilutes it to the mark with deionised water.
The student then transfers a 25.0 cm3 aliquot of this diluted solution into a conical flask and titrates it against 0.0500 mol dm-3 sulfuric acid (H2SO4\text{H}_2\text{SO}_4H2SO4).
The titration results are shown below:
| Trial | Volume of H2SO4\text{H}_2\text{SO}_4H2SO4 added (cm3\text{cm}^3cm3) |
|---|---|
| 1 (Rough) | 14.20 |
| 2 | 13.55 |
| 3 | 13.45 |
| 4 | 13.90 |
What is the concentration of sodium hydroxide in the original commercial drain cleaner?
0.338 mol dm−30.338\text{ mol dm}^{-3}0.338 mol dm−3
0.675 mol dm−30.675\text{ mol dm}^{-3}0.675 mol dm−3
1.35 mol dm−31.35\text{ mol dm}^{-3}1.35 mol dm−3
1.38 mol dm−31.38\text{ mol dm}^{-3}1.38 mol dm−3
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.