An unknown inorganic compound `(X)` gave the following reactions:
(i) The compound `(X)` on heating gave a residue, oxygen and oxide of nitrogen.
An aqueous solution of compound `(X)` on addition to tap water gave a turbidity which did not dissolve in `HO_(3+)`
(iii) The turbidity dissolved in `NH_(4)OH` .
Identify the compound `(X)` and gives equation for the reaction (i),(ii) & (iii)`