A waxy crystalline solid `(A)` with a garlic odour is obtained by burning white `P` in a stream of air and nitrogen. `(A)` reacts vigorously with hot water forming a gas `(B)` and an acid `(C )`.Gas `(B)`has unplesant odour of rotten fish and is neutral towards litmus.When passed through `AgNO_(3)` solution, gas `(B)` produces a black precipitate `(D)`.What are `(A)` to `(D)` ? Give chemical equations of the reactions.

Answer

(A)`P_(4)O_(6)`; (B)`PH_(3)`; ( C)`H_(3)PO_(4)` ; (D)`Ag`

Explanation

The given changes are :
`P_(4)+3O_(2)(s)("air")tounderset((A))(P_(4)O_(6))("Garlic odour")` , `P_(4)O_(6)+6H_(2)O ("hot") to underset(( C))(3H_(3)PO_(4)) +underset(( B))(PH_(3))`
`(B)` is `PH_(3)` having rotten fish smell and neutral towards litmus
`6Ag^(+) + PH_(3) + 3H_(2)O to H_(3)PO_(3) + underset((D))(6Ag) darr+6H^(+)`