When a brown compound of manganese (A) is treated with HCl it gives a gas (B). The gas taken in excess, reacts with `NH_(3)` to give an explosive compound (C ). Identify compound A, B and C.

Explanation

`MnO_(2)` is the brown compound of Mn which reacts with HCl to give `Cl_(2)` gas. This gas forms an explosive compound `NCl_(3)` when treated with `NH_(3)`. Thus, A = `MnO_(2), B = Cl_(2), C = NCl_(3)` and reactions are as follows
(i) `underset([A])MnO_(2)+4HCl rarr MnCl_(2) +underset([B]) Cl_(2) + 2H_(2)O`
(ii) `NH_(3) + underset(("Excess"))(3Cl_(2))rarrunderset([C])(NCl_(3))+3HCl`