An aqueous solution of a mixture of two inorganic salt , when reated with diute HCI ,Gave a precipitate (P) and a filrate (Q) .The precipitate P was found to dissolve in hot water .The filrate (Q) remained unchanged , white tracated with `H_(2)S` in a difute mineral acid medium .However it gave a precipitate (R ) with `H_(2)S` in an ammoniacal medium .THe precipitate R give a coloured solution (S ) when treated with `H_(2)O_(2)` to an aq2ueous `NaOH` medium
The coloured solution S contain

Options

A. `Fe_(2)(SO_(4))_(3)`
B. `CuSO_(4)`
C. `ZnSO_(4)`
D. `Na_(2)CrO_(4)`

Answer

d

Explanation

The precipitate `(P)` contains `Pb^(2+)`
`Pb^(2+) + 2HCI rarr PbCI^(2+) overset(Hot) underset(water)(to) Solution`
The filtrate `(Q)` contains `Cr^(+3)`, since it does give any precipitate with `H_(2)S` in acide medium .But gives precipitate`(R )` with `H_(2)S` in alkline medium So, `R` is `Cr(OH)_(3)` and S is `Na_(2)CrO`
`Cr^(+3) overset(Ammonical) underset(H_(2)S)to Cr(OH)_(3) overset(H_(2)O_(3))underset(NaOH)to underset(yellow soln)(Na_(2)CrO_(4))`