Free Acids & bases questions for IGCSE Chemistry (0620), part of Acids, bases & salts. Each question has the answer and the marking points an examiner would look for.
Generate a full Acids & Bases worksheet →All Acids, bases & salts questionsDilute hydrochloric acid and aqueous sodium hydroxide are tested.
1 Hydrochloric acid reacts with a carbonate to give hydrogen.
2 Neutralisation produces a salt and water.
3 Hydrochloric acid turns methyl orange red.
Which statements are correct?
Answer: B
Two acids, hydrochloric acid and ethanoic acid, have the same concentration. Excess magnesium ribbon is added to equal volumes of each.
How does the hydrochloric acid compare with the ethanoic acid?
| pH | initial rate of reaction | total volume of hydrogen | |
|---|---|---|---|
| A | lower | faster | the same |
| B | higher | faster | the same |
| C | lower | faster | greater |
| D | lower | the same | the same |
Answer: A
Which term is described by this statement?
“The reaction between an acid and a base to produce a salt and water.”
Answer: D
The pH scale measures acidity.
Describe how the concentration of H⁺ ions relates to pH.
Suggest why universal indicator is better than litmus for comparing two acids.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | higher [H⁺], lower pH the higher the concentration of H⁺, the lower the pH B1 | 1 |
| (b) | shows pH value / strength it shows the pH (how acidic), not just acid or alkali B1 | 1 |
Universal indicator is added to solutions of different pH.
State the colour of universal indicator in a strongly acidic solution and in a neutral solution.
Write the ionic equation for neutralisation.
Name the salt formed when sulfuric acid reacts with potassium hydroxide.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | red; green strong acid: red B1 neutral: green B1 | 2 |
| (b) | H⁺ + OH⁻ → H₂O H⁺(aq) + OH⁻(aq) → H₂O(l) B1 | 1 |
| (c) | potassium sulfate potassium sulfate B1 | 1 |
Hydrochloric acid is a strong acid and ethanoic acid is a weak acid.
Define an acid in terms of protons.
Explain the difference between a strong acid and a weak acid.
Suggest how you could show that ethanoic acid is weaker than hydrochloric acid of the same concentration.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | proton donor a proton (H⁺) donor B1 | 1 |
| (b) | fully vs partially ionised a strong acid is fully ionised in water B1 a weak acid is only partially ionised B1 | 2 |
| (c) | higher pH / slower with magnesium measure the pH: ethanoic acid has a higher pH B1 or it reacts more slowly with magnesium/carbonate B1 | 2 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in