Neutralisation and salts · Year 9
Acids react with bases, alkalis, carbonates and reactive metals to make salts. In neutralisation, hydrogen ions from the acid and hydroxide ions from the alkali join to make water. A salt’s name comes from the metal and the acid: hydrochloric acid makes chlorides, sulfuric acid makes sulfates and nitric acid makes nitrates.
Key facts
- acid + base → salt + water. Bases are metal oxides and hydroxides; alkalis are bases that dissolve in water.
- acid + metal → salt + hydrogen, and acid + carbonate → salt + water + carbon dioxide.
- Hydrochloric acid makes chlorides, sulfuric acid makes sulfates and nitric acid makes nitrates.
- The ionic equation for neutralisation is H⁺(aq) + OH⁻(aq) → H2O(l).
- To make a soluble salt, add an insoluble base or carbonate to the acid until it is in excess, filter, then crystallise. With an alkali, use a titration to find the exact amounts.
- Insoluble salts are made by mixing two solutions to form a precipitate, which is filtered, washed and dried.