An aqueous solution of a mixture of two inorganic salts, when treated with dilute HCl, gave a precipitate (P) and a filtrate (Q). The precipitate (P) was found to dissolve in hot water. The filtrate (Q) remained unchanged when treated with H2S in a dilute mineral acid medium. However, it gave a precipitate (R) with H2S in an ammoniacal medium. The precipitate R gave a coloured solution (S) when treated with H2O2 in an aqueous NaOH medium.
The coloured solution S contains
The following reactions are happening in these experiments:
From these equations, it can be seen that the solution S should contain Cr3+ ion. Hence, option D is correct.