27. Solving a chemistry problem

9. Reveal the essence of fractional and systematic methods of analysis. Suggest options for separating and detecting cations in the solutions below, which are a mixture of cations of different analytical groups, by fractional and systematic methods. Describe in detail the determination procedure in a systematic manner. Draw up equations for the corresponding reactions, indicate the conditions for the reactions to occur.
9. Ba2, Cr3, Bi3, Sn2