Question

Give the ionisation behaviour of the following salt:

Potash alum

Answer 1

Potash alum has the chemical formula is KAl(SO₄)₂.12H₂O.

When dissolved in water, potash alum dissociates completely into its constituent simple ions:

\[\ce{KAl(SO4)2 -> K+ + Al3+ + SO^2-_4}\]

In aqueous solution, potash alum furnishes:

K⁺, Al³⁺, \[\ce{SO^2-_4}\]ions

No complex ions are formed. Potash alum is a double salt that dissociates completely.