Reactions of Acids with Metals, Bases and Carbonates — AQA GCSE Chemistry
Acids react in three predictable ways. Learning these patterns lets you predict the products of many reactions.
The three reaction patterns
- acid + metal → salt + hydrogen
- acid + base (metal oxide or hydroxide) → salt + water (neutralisation)
- acid + metal carbonate → salt + water + carbon dioxide
Naming the salt
The salt formed depends on the acid used:
- Hydrochloric acid → chlorides
- Sulfuric acid → sulfates
- Nitric acid → nitrates
And the first part of the salt's name comes from the metal (e.g. copper sulfate, sodium chloride).
Example equations
- magnesium + hydrochloric acid → magnesium chloride + hydrogen
- copper oxide + sulfuric acid → copper sulfate + water
- calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide
Testing the gases
- Hydrogen — a lighted splint gives a squeaky pop.
- Carbon dioxide — bubbled through limewater, it turns cloudy.
Exam tips
- Memorise the three reaction patterns and their products.
- Match the acid to its salt: chloride / sulfate / nitrate.
- Carbonates also release carbon dioxide (test with limewater).
- Be able to write word and balanced symbol equations for these reactions.