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Practise 22 exam-style questions on Neutralisation of acids and salt production for AQA GCSE Chemistry. Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.
Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.
Name the salt formed when dilute hydrochloric acid reacts with calcium hydroxide.
Calcium chloride.
Hydrochloric acid produces chlorides, and the positive ion (calcium) comes from the calcium hydroxide. The other product is water.
calcium chloride
allow CaCl₂; do not accept calcium chlorate
A metal carbonate reacts with an acid and gives off a gas.
Describe a test to show that the gas is carbon dioxide. Give the result.
Bubble the gas through limewater. If the gas is carbon dioxide, the limewater turns milky.
Carbon dioxide reacts with limewater (calcium hydroxide solution) to form insoluble calcium carbonate, which makes the limewater cloudy. A burning splint being put out is not a reliable test, because other gases can do that too.
bubble the gas through limewater
allow shake the gas with limewater; allow calcium hydroxide solution
the limewater turns milky / cloudy
allow white precipitate
Sodium carbonate powder reacts with dilute hydrochloric acid to produce sodium chloride solution, water and carbon dioxide gas.
Write a balanced symbol equation for this reaction. Include state symbols.
Na₂CO₃(s) + 2HCl(aq) → 2NaCl(aq) + H₂O(l) + CO₂(g)
Sodium carbonate contains two Na⁺ ions, so two NaCl form and two HCl are needed. The question says sodium carbonate is a powder, so it is (s), the salt is in solution (aq), water is (l) and carbon dioxide is (g).
correct formulae: Na₂CO₃ + HCl → NaCl + H₂O + CO₂
balanced: Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂
allow multiples
state symbols: Na₂CO₃(s), HCl(aq), NaCl(aq), H₂O(l), CO₂(g)
allow state symbols mark on an equation with correct formulae even if not balanced
A student added four different substances, P, Q, R and S, to separate samples of dilute hydrochloric acid. The table shows the observations.
Identify which substance is a metal carbonate and which is an alkali. Name the gas produced by P and the gas produced by S.
P is the metal carbonate and R is the alkali. P produces carbon dioxide and S produces hydrogen.
Carbonates fizz with acids because they give off carbon dioxide; metals such as magnesium also fizz, but they give off hydrogen. An alkali is a solution that neutralises the acid without fizzing, but the temperature rises. Q is a metal oxide (copper(II) oxide), which dissolves to form a coloured salt solution.
P is the metal carbonate
R is the alkali
gas from P is carbon dioxide
allow CO₂
gas from S is hydrogen
allow H₂
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