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Water - Solubility - Ions

Tests for Ions.

How can Ions be Detected?

Ions can be divided into positive ions and negative ions.
Positive ions are metal ions or ammonium.
Negative ions are non-metal ions.

Positive ions can be detected in a solid
using a flame test (if the metal gives a coloured flame)
or in solution with sodium hydroxide.

Negative ions can be detected in solution by using
1.  a dilute acid for carbonate and sulfite
2.  dilute hydrochloric acid and barium chloride for sulfate
3.  dilute nitric acid and silver nitrate for chloride, bromide and iodide
4.  aluminium powder and sodium hydroxide solution for nitrate.

Some carbonates show a
colour change during thermal decomposition.

Hydrogen ions and hydroxide ions can
be detected using acid/base indicators.

There are a number of
instrumental methods for the detection of ions.

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