A coloured solution known to contain two metal ions of different groups, was treated with excess cold sodium hydroxide solution. When filtered a whitish solid, slowly changing to brown, was retained on the filter paper and a colourless solution collected as the filtrate. Drop wise adition of hydrochloric acid to the filtrate produced a white precipitate which dissolved in excess acid. Treatment of the residue from the filter paper with a strong oxidiser, PbO_(2) and concentratedHNO_(3) on boiling produced a reddish-violet (purple) solution. Reddish-violet solution obtained by oxidation is of:

A coloured solution known to contain two metal ions of different group

1.	A coloured solution known to contain two metal ions of different groups, was treated with excess cold sodium hydroxide solution. When filtered a whitish solid, slowly changing to brown, was retained on the filter paper and a colourless solution collected as the filtrate. Drop wise adition of hydrochloric acid to the filtrate produced a white precipitate which dissolved in excess acid. Treatment of the residue from the filter paper with a strong oxidiser, PbO_(2) and concentratedHNO_(3) on boiling produced a reddish-violet (purple) solution. Reddish-violet solution obtained by oxidation is of:
Answer» `ZnO_(2)^(2-)` `MnO_(4)^(2-)` `MnO_(4)^(-)` `MnO_(2)` Answer :C