Propanoic acid (C2H5COOH\text{C}_2\text{H}_5\text{COOH}C2H5COOH) is a weak acid.
The acid dissociation constant (KaK_aKa) for propanoic acid is 1.35×10−5 mol dm−31.35 \times 10^{-5}\text{ mol dm}^{-3}1.35×10−5 mol dm−3 at 25 ∘C25\text{ }^\circ\text{C}25 ∘C.
State the meaning of the term weak acid.
Give an expression for the acid dissociation constant for propanoic acid.
A student dilutes 15.0 cm315.0\text{ cm}^315.0 cm3 of 0.600 mol dm−30.600\text{ mol dm}^{-3}0.600 mol dm−3 propanoic acid by adding distilled water until the total volume is 250.0 cm3250.0\text{ cm}^3250.0 cm3.
Calculate the pH of this diluted solution of propanoic acid.
Give your answer to 2 decimal places.
A buffer solution with a pH of 4.854.854.85 is made by dissolving m gm\text{ g}m g of sodium propanoate (C2H5COONa\text{C}_2\text{H}_5\text{COONa}C2H5COONa) in a solution of propanoic acid. The final volume of buffer solution is 500 cm3500\text{ cm}^3500 cm3 and the final concentration of the propanoic acid is 0.250 mol dm−30.250\text{ mol dm}^{-3}0.250 mol dm−3.
Calculate mmm in ggg.
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.