Question

What reagent can be used to test for the presence of sulfate ions ?

Answer 1

Barium chloride solution can be used.

Explanation:

Barium sulfate is insoluble so forms a precipitate:

`CuSO_(4(aq))+BaCl_(2(aq))rarrBaSO_(4(s))+CuCl_(2(aq)`

Omitting the spectator ions:

`Ba_((aq))^(2+)+SO_(4(aq))^(2-)rarrBaSO_(4(s))`