A black compound of manganese reacts with a halogen acid to give greenish yellow gas. When excess of this gas reacts with `NH_(3) an unstable trihalide is formed. In this process the oxidation state of nitrogen changes from . . . . . . . . . .

Options

A. `-3to 0`
B. `-3 to 0`
C. `-3 to + 5`
D. `0 to -3`

Answer

A

Explanation

Black coloured compound `MnO_(2)` reacts with HCl to produce greenish yellow coloured gas of `Cl_(2)`
`underset("Black")(MnO_(2))+4HCl toMnCl_(2)+underset(("greenish yellow gas"))(2H_(2)O+Cl_(2)`
`Cl_(2)` on further treatment with `NH_(3)` produces `NCl_(3)`
`overset(-3)NH_(3)+3Cl_(2)tooverset(+3)NCl_(3)+3HCl`
`NH_(3)(-3)` changes to `NCl_(3)(+3)` in the above reaction . Hence, (a) is the correct choice.