Answer :
The test for [tex]SO^{2-}_4[/tex] ion :
Procedure :
1) In a test tube, add 5-10 drops of aqueous solution of [tex]SO^{2-}_4[/tex].
2) Add 1-2 ml of HCl solution and Barium chloride solution in the test tube.
The formation of white precipitate indicates the presence of [tex]SO^{2-}_4[/tex] ion.
The chemical reaction is,
[tex]BaCl_2(aq)+SO^{2-}_4(aq)\rightarrow BaSO_4(aq)[/tex]
The White precipitate of [tex]BaSo_4[/tex] formed in this reaction.