CSEC Chemistry · May/June 2008 · Paper 2 · Question 1(a)(iii)

A strong acid-base titration is performed, and pH changes are measured using a pH meter to determine the end point. The end point is expected to be a sharp pH change at 7.0. Figure 1 shows ten pH readings from an experiment where 20.0 cm³ of 0.005 mol dm⁻³ sulphuric acid is titrated with sodium hydroxide of unknown concentration. Reading I is the initial pH of the sulphuric acid, and readings II to X are pH values after adding various volumes of sodium hydroxide, as indicated in Figure 1.

Using the graph paper provided on page 5 and the data in Table 1, plot a graph of pH against volume of sodium hydroxide added.

This question uses a figure or table from the paper — you'll see it when you practise.