An environmental chemist is monitoring the alkaline run-off from a construction site. They titrate a 25.0 cm325.0\text{ cm}^325.0 cm3 sample of wastewater containing barium hydroxide (Ba(OH)2\text{Ba(OH)}_2Ba(OH)2) against a standard solution of 0.125 mol/dm30.125\text{ mol/dm}^30.125 mol/dm3 hydrochloric acid (HCl\text{HCl}HCl).
They find that exactly 22.4 cm322.4\text{ cm}^322.4 cm3 of the hydrochloric acid is required to completely neutralise the barium hydroxide.
The equation for the reaction is:
Ba(OH)2+2HCl→BaCl2+2H2O \text{Ba(OH)}_2 + 2\text{HCl} \rightarrow \text{BaCl}_2 + 2\text{H}_2\text{O} Ba(OH)2+2HCl→BaCl2+2H2OCalculate the concentration of the barium hydroxide solution in mol/dm3\text{mol/dm}^3mol/dm3 and in g/dm3\text{g/dm}^3g/dm3.
Relative atomic masses (ArA_rAr): H=1\text{H} = 1H=1, O=16\text{O} = 16O=16, Ba=137\text{Ba} = 137Ba=137
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.