A colourless inorganic salt (A) decomposes completely at about `25^(@)C` to give only two products, (B) and (C ), leaving no residue. The product (C ) is a liquid at room temperature and neutral to moist litmus paper while the gas (B) is a neutral oxide. White phosphorus burns in excess of (B) to produce a strong white dehydrating agent. Write balanced equations for the reactions involved in the above process.

Explanation

(i) Since a colourless inorganic salt (A) on heating to `250^(@)`C decomposes to form two oxides (B) and (C) leaving no residue, therfore, compound (A) must be ammonium nitrate `(NH_(4)NO_(3))`.
`underset((A))(NH_(4)NO_(4)) overset(250^(@)C) (rarr) underset((B)) (N_(2)O) underset((C)) (2H_(2)O)`
(ii) The fact that inorganic salt (A) is actually ammonium nitrate is confirmed by the observation that oxide (C), i.e., `H_(2)O` is a liquid at room temperature.
(iii) If the oxide (C) is `H_(2)O` then the other neutral oxide (B) must be nitrous oxide, `N_(2)O`.
(iv) The fact that the neutral oxide (B) is actually `N_(2)O` is confirmed by the observation that white phosphorus burns in `N_(2)O` to form phosphorus pentoxide which is a strong dehydrating agent.
`underset("Nitrous oxide (B)")(10 N_(2)O) + P_(4) rarr underset("pentoxide")underset("Phosphorus")(P_(4)O_(10)) + 10 N_(2)`
Thus, inorganic salt (A) is ammonium nitrate `(NH_(4)NO_(3))`, (B) is nitrous oxide `(N_(2)O)` and (C) is water `(H_(2)O)`.