1.1. i) State what is meant by a Brønsted–Lowry base.

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ii) Explain what is meant by a weak acid.

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1.2. A student titrated 0.10 mol dm^-3 acid into a conical flask containing 25.0 cm³ of 0.10 mol dm^-3 of a base, recording the pH with each addition of acid. The student repeated the procedure using different combinations of acids and bases.

Fig. 5.1

Identify the curve in Fig. 5.1 that represents the titration of:

i) Ammonia and ethanoic acid.

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ii) Ammonia and nitric acid.

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iii) Sodium hydroxide and propanoic acid.

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1.3. Identify which indicator in Table 5.2 would be most suitable for curve Z. Explain your answer.

Table 5.2

1.4. Water is amphoteric and will react with nitric acid and ammonia.

i) Construct an equation to show how water reacts with ammonia.

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ii) State what is meant by the term amphoteric.

[1]