Explain a solution that may contain any of the group 3 cations. Treatment of the solution with ClO-in alkaline medium yields a yellow solution as well as colored precipitate. Explain the acidified solution is unaffected by treatment with NH 4 OH. The colored precipitate dissolves in nitric acid addition of excess NH 4 OH to this acidic solution produces merely a blue solution. Which group three ions are present? Which are absent? Which are doubts? How would you remove all doubt?