Making salts

Salts are useful compounds. Chemists make them by reacting acids with metals, bases or carbonates.

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Naming salts

A salt forms when the hydrogen in an acid is replaced by a metal.
The first part of the name comes from the metal; the second part comes from the acid:
hydrochloric acid → chloride; sulfuric acid → sulfate; nitric acid → nitrate.
Examples: zinc + hydrochloric acid gives zinc chloride; copper oxide + sulfuric acid gives copper sulfate.

Reactions that make salts

acid + metal → salt + hydrogen
acid + alkali → salt + water
acid + metal oxide → salt + water (metal oxides are bases)
acid + metal carbonate → salt + water + carbon dioxide
Test for carbon dioxide: bubble it through limewater, which turns milky (cloudy).

Making copper sulfate crystals

1. Warm some dilute sulfuric acid.
2. Add black copper oxide a little at a time, stirring, until no more dissolves (the copper oxide is now in excess, so all the acid has reacted).
3. Filter to remove the leftover copper oxide.
4. Heat the blue filtrate to evaporate some of the water, then leave it to cool and crystallise.
5. Dry the crystals on filter paper.
Worked example

An empty evaporating basin has a mass of 52.3 g. With the dry crystals in it, the mass is 55.1 g. What mass of crystals was made?

  1. Mass of crystals = full basin − empty basin
  2. 55.1 − 52.3

Answer: 2.8 g

Key idea

Salt names: metal first, then chloride (hydrochloric), sulfate (sulfuric) or nitrate (nitric). Acid + metal → salt + hydrogen; acid + base or alkali → salt + water; acid + carbonate → salt + water + carbon dioxide. Excess base, filter, evaporate, crystallise.

Key words
Acid
A substance with a pH below 7. Acids turn universal indicator red, orange or yellow and turn blue litmus red.
Alkali
A base that dissolves in water. Alkalis have a pH above 7 and turn universal indicator blue or purple.
Water
Pure water melts at 0 °C and boils at 100 °C. Its density is 1 g/cm³. Ice is less dense than water, so it floats.

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2 more questions

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  1. Name the salt made when magnesium reacts with hydrochloric acid.

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    Answer: magnesium chloride

    Hydrochloric acid makes chlorides: magnesium chloride (and hydrogen).

  2. Which acid would you use to make zinc chloride?

    1. Hydrochloric acid
    2. Nitric acid
    3. Sulfuric acid
    4. Citric acid
    Show the answer

    Answer: Hydrochloric acid

    Hydrochloric acid makes chlorides.

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Sources and references

Checked by the GCSE-ready editorial team, 17 October 2026. Last updated 2 October 2026. Spotted a mistake? Tell us and we will fix it.

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