Making Salts Methods

Authors Avatar by ro5sh923 (student)

Making Salts – GCSE Notes

Making Soluble Salts

To make a soluble salt, an acid is neutralised by adding a metal, a solid base, a solid metal carbonate, or a solution of an alkali. Soluble salts can be made by the process of:

  • Titration
  • Excess Reactant


Titration methods are carried out for a soluble base (an alkali) reacting with an acid to produce a soluble salt, e.g. reacting sodium hydroxide with hydrochloric acid to make sodium chloride. The problem with the reaction of a soluble base reaction with acid is that once all the acid has reacted, any excess base will not be visible; so there is no signal that all the acid has been neutralised. Therefore, the problem can be overcome by adding a third chemical into the reaction mixture called an indicator. Indicators are chemicals that change colour with a change in ph. The indicator is added to the acid and as the soluble base is added, the pH of the solution is raised until all the acid has reacted (been neutralized). The experiment can be run a number of times to gain a more accurate average value for the volume of base that needs to be added to neutralise the acid used. Once this accurate value has been determined, the experiment can be run one last time without any indicator. The volume of base that is required can be added carefully from the burette to produce a colourless solution, instead of the coloured solutions produced when indicator is added. This clear colourless solution can be heated to encourage crystals to form and then left to cool down slowly so that large crystals can form.

Join now!

Excess Reactant

Excess Reactant methods are carried out for a metal or insoluble base reacting with an aid to produce a soluble salt e.g. reacting copper(II) oxide with sulphuric acid to make copper(II) sulphate. The first stage is the addition of the base to the acid. The base is added until no more visible reaction can be seen i.e. the base no longer dissolves, no more effervescence occurs. The mixture is then filtered to remove the excess solid and leave a clear solution in the evaporating bowl. The solution can be gently heated to remove some of the water and ...

This is a preview of the whole essay