Reactions of acids with metals — AQA GCSE Chemistry
Test yourself on Reactions of acids with metals with AQA GCSE practice questions.
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Reactions of acids with metals explained
When an acid reacts with a reactive metal, the metal atoms lose electrons and hydrogen ions in the acid gain electrons, producing hydrogen gas.
Read the full explanation
The other product is a salt formed from the metal ion and the acid's negative ion. For example, magnesium reacts with hydrochloric acid to give magnesium chloride and hydrogen: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g). The salt name depends on the acid: hydrochloric acid gives chlorides, sulfuric acid gives sulfates. Not all metals react; those below hydrogen in the reactivity series, such as copper, do not react with dilute acids. The reaction is observed as effervescence as hydrogen bubbles form, and the metal gradually dissolves. Testing the gas with a lit splint gives a squeaky pop, confirming hydrogen.
Your focus
- Write word and balanced symbol equations for reactions of acids with metals.
- Name the salt produced from a given metal and acid.
- Describe the test and observation for hydrogen gas.
Reactions of acids with metals exam tips
Marking Points
- Name the salt from the metal and the acid used, for example magnesium sulfate from magnesium and sulfuric acid.
- Write a balanced symbol equation with the correct state symbols where required.
- State that hydrogen gas is produced and describe the test for hydrogen.
- Explain that the metal must be more reactive than hydrogen for the reaction to occur.
- Describe observations such as effervescence and the metal dissolving.
Examiner Tips
- 💡Write the word equation first to fix the salt name, then convert to a balanced symbol equation.
- 💡Include state symbols when the question asks for a full equation.
- 💡Link the squeaky pop test directly to hydrogen rather than to oxygen or carbon dioxide.
Common Mistakes
- Naming the salt from the acid only, for example calling the product 'hydrochloric acid salt'; the correction is to combine the metal name with the acid-derived ending, such as magnesium chloride.
- Writing an unbalanced equation such as Mg + HCl → MgCl₂ + H₂; the correction is to balance to Mg + 2HCl → MgCl₂ + H₂.
- Claiming all metals react with acids; the correction is that metals below hydrogen in the reactivity series, such as copper, do not react with dilute acids.