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IGCSE · Practice questions · Properties of acids and bases

Every acid makes a salt.

Six original Cambridge-style questions on the properties of acids and bases: indicators, word and symbol equations, and identifying products.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
Keep these straight

Four patterns, one salt.

01
Recall
[3 marks]

State the colour of (a) litmus, (b) methyl orange and (c) thymolphthalein in an alkaline solution.

  • (a) blue ✓
  • (b) yellow ✓
  • (c) blue ✓
02
Recall
[3 marks]

Write word equations for the reactions of dilute hydrochloric acid with (a) zinc, (b) calcium oxide and (c) sodium carbonate.

  • (a) zinc + hydrochloric acid → zinc chloride + hydrogen ✓
  • (b) calcium oxide + hydrochloric acid → calcium chloride + water ✓
  • (c) sodium carbonate + hydrochloric acid → sodium chloride + water + carbon dioxide ✓
03
Recall
[2 marks]

Write the balanced symbol equation for the reaction of magnesium with dilute sulfuric acid, and describe one observation.

  • Mg + H2SO4 → MgSO4 + H2 ✓
  • Fizzing (bubbles) and the magnesium gets smaller or disappears. ✓
04
Explain
[2 marks]

Explain the difference between a base and an alkali, giving one example of each.

  • A base reacts with an acid to form a salt and water; an alkali is a base that dissolves in water. ✓
  • Example base: copper(II) oxide (insoluble). Example alkali: sodium hydroxide. ✓
05
Analysis
[2 marks]

Describe a test to show that a fertiliser contains ammonium ions.

  • Warm the fertiliser with aqueous sodium hydroxide. ✓
  • Ammonia is given off, which turns damp red litmus paper blue. ✓
06
Recall
[2 marks]

Write the ionic equation, with state symbols, for the reaction between any acid and any alkali, and name the type of reaction.

  • H+(aq) + OH−(aq) → H2O(l) ✓
  • Neutralisation. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.