The oxide,which is neither acidic nor basic is

Nitric oxide $(NO)$ is prepared by the action of dilute $HNO_3$ on which of the following metals?

How can you explain the higher stability of $BCl_3$ as compared to $TlCl_3$?

Orthophosphorus acid on disproportionation gives $PH_3$ and another oxoacid of phosphorus '$X$'. The basicity of $X$ is

Identify the incorrect statements about group $15$ elements :
$A$. Dinitrogen is a diatomic gas which acts like an inert gas at room temperature.
$B$. The common oxidation states of these elements are $-3, +3$ and $+5$.
$C$. Nitrogen has unique ability to form $p\pi-p\pi$ multiple bonds.
$D$. The stability of $+5$ oxidation states increases down the group.
$E$. Nitrogen shows a maximum covalency of $6$.
Choose the correct answer from the options given below.

The oxoacid of phosphorus that is easily obtained from a reaction of alkali and white phosphorus and has two $P-H$ bonds,is