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Preliminary Lab Manual
Colour, Texture and Solubility
A preliminary examination to note
the appearance, colour and the solubility of the unknown
substance often gives clues to the identity of the unknown
chemical or the element present in the substance.
In general, compounds of transition
metals and solutions containing transition metal ions
have characteristic colours.
Group I, II, and III metals form
white salts and colourless metal ions in solution.
Most metals in the laboratory, with
the exception of copper, are usually silvery grey or
grey with a shiny lustre.
Ionic compounds which are
soluble in water form solutions. The solubility of a
sample is usually tested first in cold water. Whether
a salt is soluble or insoluble in water gives us a clue
to the type of anion present in the salt sample. If
an ionic salt dissolves in water, the colour of the
solution formed can indicate the possible identity of
the cation present in the salt sample
The solubilities of some common
ionic salts in water is summarised in the Solubility
Table.
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