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. White solid changing to brown is due to formation 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. White solid changing to brown is due to formation of:
Answer» `Mn(OH)_(2)` `MgO` `AI(OH)_(3)` `MNO(OH)_(2)` ANSWER :D