Preparation of Salts

Soluble salts can be prepared by reacting an acid with a base, a process known as neutralisation. The general formula is: acid + base -> salt + water.
A common example is the reaction between sulfuric acid and sodium hydroxide, which creates sodium sulfate: H2SO4 + 2NaOH -> Na2SO4 + 2H2O.
You must ensure that the reaction is complete by adding the base until there is no more fizzing or until the acid is in excess, which indicates all of it has reacted.
The mixture can be heated to evaporate water and get the salt.

A soluble salt can also be prepared by reacting an acid with a metal carbonate or a hydrogen carbonate.
The general formula for this reaction is: acid + carbonate -> salt + water + carbon dioxide.
An example of this type of reaction is between hydrochloric acid and sodium carbonate to produce sodium chloride: 2HCl + Na2CO3 -> 2NaCl + H2O + CO2.
The salt product can be separated from the remaining solution through filtration and the salt can then be obtained from the filtrate through crystallisation or evaporation.

Insoluble salts can be prepared via a precipitation reaction. This process occurs when two solutions that contain ions that can combine to form an insoluble compound are mixed together.
For example, silver nitrate (AgNO3) mixed with sodium chloride (NaCl) will produce insoluble silver chloride (AgCl): AgNO3 + NaCl -> AgCl + NaNO3.
The insoluble salt, or precipitate, can be collected by filtration, washed to remove any remaining ions, and then dried.

Salts can also be prepared by direct combination of an element with an element, an element with a compound, or a compound with a compound.
For example, the reaction of chlorine gas with sodium metal produces sodium chloride: 2Na(s) + Cl2(g) -> 2NaCl(s).