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Acids, bases and titration — Question 23

QCAA 2024, Paper 1 · 5 marks

Q23 · 2024 · Paper 1Unclassified5 marks

QUESTION 23 (5 marks)

An aqueous solution of sodium hydroxide (NaOH) was titrated against a 30.0 mL aliquot of a 0.012 M potassium hydrogen phthalate (KHP) standard aqueous solution. The balanced chemical equation for the reaction is shown.

The results are shown in the titration curve.

Chemistry question figure

a) Determine whether KHP is a strong or weak acid. Identify one feature from the titration curve to support your reasoning.

[2 marks]

b) Explain why KHP(aq) is used as the standard solution rather than NaOH(aq).

[1 mark]

c) Calculate the concentration of NaOH(aq). Show your working.

[2 marks]

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