Eduqas A Level Chemistry
Eduqas A Level Chemistry PI5.2 Acid-base Equilibria Exam Questions
Free Eduqas A Level Chemistry exam questions on PI5.2 Acid-base Equilibria, with mark schemes. Covers Ka, pH of weak acids, Kw, buffers and titration curves.
PI5.2 Acid-base Equilibria exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
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A Level Chemistry Flashcards
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About Eduqas A Level Chemistry PI5.2 Acid-base Equilibria
This topic covers quantitative acid-base chemistry.
What you need to know
- Weak acids Ka = [H⁺][A⁻] / [HA]; pH from Ka and concentration.
- Kw Kw = [H⁺][OH⁻] = 1.0 x 10⁻¹⁴ at 298 K; pH of strong bases.
- Buffers Resist pH change; pH = pKa when [HA] = [A⁻].
- Titration curves Shapes for strong and weak acids and bases, and choosing indicators.
Common mistakes in PI5.2 Acid-base Equilibria
- Using pH = −log of concentration for weak acids.
- Forgetting Kw changes with temperature.
- Choosing an indicator outside the vertical section.
Try three PI5.2 Acid-base Equilibria exam-style questions
1. Calculate the pH of 0.10 mol dm⁻³ ethanoic acid (Ka = 1.7 x 10⁻⁵). (2 marks)
Show the mark scheme answer
[H⁺] = √(1.7 x 10⁻⁶) = 1.30 x 10⁻³ (1); pH = 2.89 (1).
2. Explain how an ethanoate buffer resists added acid. (2 marks)
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Added H⁺ reacts with ethanoate ions to form ethanoic acid (1), so [H⁺] changes very little (1).
3. State the pH of a neutral solution at 298 K. (1 mark)
Show the mark scheme answer
7.
PI5.2 Acid-base Equilibria FAQs
What does Acid-base Equilibria cover?
Ka, Kw, pH calculations, buffers and titration curves.
Which practical links here?
Measuring titration curves with a pH meter.
How is buffer pH calculated?
[H⁺] = Ka x [HA] / [A⁻].
Revise this topic with flashcards: A Level Chemistry Flashcards, with mark scheme answers for Anki and Quizlet.
