You are given a mixture of two cations. When this mixture was treated with 6 M HCL there was no precipitate. It gave a black precipitate in acidic pH with 1 M Thioacetamide. When this black precipitate was treated with 6 M Ammonia and adjusting the pH to 4. This solution was treated with 0.1M Potassium ferrocyanide gave a red-brown precipitate.
The filtrate after the removal of the black precipitate was basified with 6M ammonia. This when treated with 3M ammonium carbonate, it gave a white precipitate. This white precipitate was dissolved in 6M acetic acid and basified with ammonia(6M). This solution gave a white precipitate with 0.1M Potassium ferrocyanide. What are the two cations?