A solution may contain any of the Group III cations. Treatment of the solutio with CIO- in alkaline medium yields a yellow solution and a colored precipitate. The acidified solution is unaffected by treatment with NH3. The colored precipitate dissolves in nitric acid; addition of excess NH3 to this acid solution produces only a blue solution. On the basis of this information, which Group III cations are present, absent, or still in doubt?
a) present?
b) absent?
c) In doubt?