Question

Suppose you have a solution that might contain any or all of the following cations: Ni²⁺, Ag⁺, Sr²⁺, and Mn²⁺. Addition of HCl solution causes a precipitate to form. After filtering off the precipitate, H₂SO₄ solution is added to the resulting solution and another precipitate forms. This is filtered off, and a solution of NaOH is added to the resulting solution. No precipitate is observed. Which ions are present in each of the precipitates? Which of the four ions listed above must be absent from the original solution?