Calcium hydroxide is sparingly soluble in water, but reacts completely with dilute nitric acid.
Ca(OH)2(s)+2HNO3(aq)→Ca(NO3)2(aq)+2H2O(l) \text{Ca(OH)}_2(\text{s}) + 2\text{HNO}_3(\text{aq}) \rightarrow \text{Ca(NO}_3)_2(\text{aq}) + 2\text{H}_2\text{O}(\text{l}) Ca(OH)2(s)+2HNO3(aq)→Ca(NO3)2(aq)+2H2O(l)A chemist adds 250 cm3250\text{ cm}^3250 cm3 of 0.0800 mol dm−30.0800\text{ mol dm}^{-3}0.0800 mol dm−3 nitric acid to 1.20 g1.20\text{ g}1.20 g of solid calcium hydroxide.
Show, by calculation, that the calcium hydroxide is in excess.
The final mixture contains a saturated solution of Ca(OH)2\text{Ca(OH)}_2Ca(OH)2 at 310 K310\text{ K}310 K.
At 310 K310\text{ K}310 K:
Calculate the pH of this solution at 310 K310\text{ K}310 K. Give your answer to two decimal places. (Assume the molar mass of Ca(OH)2\text{Ca(OH)}_2Ca(OH)2 is 74.1 g mol−174.1\text{ g mol}^{-1}74.1 g mol−1.)
77 exam-style questions on AQA A Level Chemistry Acids and bases (A-level only), covering Brønsted–Lowry acid–base equilibria in aqueous solution (A-level only), Definition and determination of pH (A-level only), The ionic product of water, $K_w$ (A-level only), Weak acids and bases $K_a$ for weak acids (A-level only), pH curves, titrations and indicators (A-level only), and Buffer action (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.