gcsescience.com                                          20                                          gcsescience.com

Acids and Alkalis

What is an Alkali?

An alkali is any substance that produces OH^-  ions in water.
Compare this with the definition of an definition of an acid.
OH^-  ions are called hydroxide ions.

An alkali has a pH of more than 7.
See examples of alkalis and properties and uses of alkalis.

What is a Base?

A substance that will neutralise an acid,
but does not dissolve in water, is called a base.
For example,
copper(II) oxide, iron(II) oxide and zinc carbonate are bases,
they do not dissolve in water
(see salts made from bases or carbonates).

Any base that dissolves in water is called an alkali.
For example, sodium hydroxide,
potassium hydroxide and sodium carbonate are alkalis.

          Links           Alkalis           Revision Questions          

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