A biochemist plans to make up a buffer solution with a pH of 5.000.
The biochemist adds solid sodium ethanoate, CH3COONa, to 400 cm3 of 0.200 mol dm–3
Ka for ethanoic acid = 1.75 × 10–5 mol dm–3
Calculate the mass of sodium ethanoate that the biochemist needs to dissolve in the ethanoic
acid to prepare this buffer solution.
Assume that the volume of the solution remains constant at 400 cm3 on dissolving the sodium
The mark scheme says that the answer is 11.48g but I don't understand how they got there and the calculations in the mark scheme are very confusing. Can someone help?