With excess of water,$PCl_5$ gives

Two oxides of nitrogen, $NO$ and $NO_2$, react together at $253 \ K$ to form a compound of nitrogen $X$. $X$ reacts with water to yield another compound of nitrogen $Y$. The shape of the anion of $Y$ is:

$NH_3 + O_2 \xrightarrow[\Delta ]{Pt} A + H_2O;$ $A + O_2 \to B;$ $B + O_2 + H_2O \to C$
$A, B$ and $C$ are

On passing a gas,$X$,through Nessler's reagent,a brown precipitate is obtained. The gas $X$ is

When aluminium phosphide is treated with dil. sulphuric acid,which gas is evolved?

Strong reducing behaviour of $H_3PO_2$ is due to