This Wikipedia content is licensed under the GNU Free Documentation License.
Precipitate
A precipitate is a solid that is formed during a chemical reaction. Precipitate formation is useful in detecting the type of cation in an unknown salt. To do this, an alkali first reacts with the unknown salt to produce a precipitate which is the hydroxide of the unknown salt. To identify the cation, the colour of the precipitate and its solubility in excess are noted.