9-1 Chemistry/Identification of ions

Flame tests can be used to identify some cations (positive ions).

Flame tests
If a sample containing a mixture of ions is used, some flame colours can be masked.

Metal hydroxides
Sodium hydroxide solution can be used to identify some cations: Ions form white precipitates when sodium hydroxide solution is added but only the aluminium hydroxide precipitate dissolves in excess sodium hydroxide solution.
 * Aluminium
 * Calcium
 * Magnesium