An aqueoussolution of a mixture of two inorganic salts, when treated with dilute $$HCL$$, gave a precipitate (P) and filtrate (Q). The precipitate P was found to dissolve in hot. water. The filtrate (Q) remained unchanged, when treated with $$H_{2}S$$ in a dilute mineral acid medium. However,it gave a precipitate (R) with $$H_{2}S$$ in an ammoniacal medium. The precipitate R gave a coloured solution (S), when treated with $$H_{2}O_{2}$$ in an
aqueous $$NaOH$$ medium.