I`ve got some kind of quiz here, which my teacher has given to me:
There`s a substance A:
-with NaOH(aq) there's a precipitate which can be solved in acids
-with BaCl2 there's a white precipitate which cannot be solved in acids
-in with NH3+H2O+H2S there will be some black solid
-with KSCN(aq) there wont be some colorful reaction
Out of reaction 2 I guess the Anion is the Sulfate-anion;
but I don't know what's the Kation.
Can somebody please help me?