gcsescience.com                                          26                                          gcsescience.com

Acids and Alkalis

Neutralisation and Salts.

What is Neutralisation?

A pH of 7 is neutral. An acid has a pH of less than 7.
An alkali has a pH of more than 7.

An acid is neutralised when it reacts with
an alkali, a base a carbonate or a metal.
When neutralisation is complete there is no more acid left,
the pH is 7 and the solution will contain a neutral salt.

See the ionic equation for neutralisation.
Neutralisation reactions are often exothermic.

What is a Salt?

When an acid is neutralised the hydrogen ion of the acid is replaced
by a positive ion from the alkali, base, carbonate or metal.
The ionic compound that is formed is called a salt (see ionic equations).
Some salts are used to make fireworks.

A salt can be soluble (it dissolves in water)
or insoluble (it does not dissolve in water).

Click on the links below for examples of

1) Salts made from an acid with a metal.

2) Salts made from an acid and a base.

3) Salts made from an acid and a carbonate.

4) Soluble salts made from an acid and an alkali.

5) Insoluble salts made from an acid or alkali or another salt.

6) Reactions of elements to make a salt.

       Links        Acids and Alkalis         Revision Questions       

gcsescience.com    The Periodic Table    Index    Neutralisation Quiz    gcsescience.com