(i) A white solid mixture of two salts containing a common cations in insoluble in water. It dissolves in dilute HCl producing some gases (with effervescence) that turn an acidified dichromate solution gren. After the gases are passed through the acidified dichromate solution, the emerging gas turns baryta water milky.
(ii) On treatment with dilute `HNO_(3)`, the white solid gives a solution which does not directly give a precipitate with a `BaCl_(2)` solution but gives a white precipitate when warmed with `H_(2)O_(2)` and then treated with a `BaCl_(2)` solution.
(iii) The solution of the mixture in dilute HCl, when treated with `NH_(4)Cl,NH_(4)OH and ` an `Na_(2)HPO_(4)` solution, gives a white precipitate.
Q. The white precipitate obtained in (iii) consists of:

Options

A. `Ba_(3)(PO_(4))_(2)`
B. `Sr_(3)(PO_(4))_(2)`
C. `Ca_(3)(PO_(4))_(2)`
D. `MgNH_(4)PO_(4)*6H_(2)O`

Answer

D