A hydrated salt (x) gives golden yellow colour in flame test, given basic gas on treatement with `NaOH`, gives yellow ppt. on treatment with `(NH_(4))_(2)MoO_(4)` and `HNO_(3)`. It gives blue bead with `Co^(2+)` salt. The salt (x) is:

Options

A. `NaAIO_(2).2H_(2)O`
B. `Na_(2)SO_(4).10H_(2)O`
C. `Na_(2)B_(4)O_(7).10H_(2)O`
D. `NaNH_(4)HPO_(4).4H_(2)O`

Answer

D

Explanation

`HPO_(4)^(2-)+3NH_(4)^(+) +12MnO_(4)^(2-)+23H^(+)`
`rarr underset("canary yellow ppt")((NH_(4))_(3)[P(Mo_(3)O_(10))_(4)]darr+12H_(2)O)`
`NaPO_(3)+CoO rarr NaCoPO_(4)` (Blue bead)