Which of the following gases is inert at room temperature?

Given below are two statements:
Statement $I$: The halogen that makes the longest bond with hydrogen in $HX$ has the smallest covalent radius in its group.
Statement $II$: $A$ group $15$ element's hydride $EH_3$ has the lowest boiling point among corresponding hydrides of other group $15$ elements. The maximum covalency of that element $E$ is $4$.
In the light of the above statements, choose the correct answer from the options given below.

The total number of $\sigma$ and $\pi$-bonds in pyrophosphoric acid are respectively

White phosphorus is heated with concentrated $NaOH$ in $CO_2$ atmosphere to form a gas $A$ and compound $B$. When $A$ is bubbled into aqueous $CuSO_4$ solution,copper phosphide and $C$ are formed. $B$ and $C$ are respectively:

In group $-15$,as we move from $N$ to $Bi$,the $M_2O_3$ type oxides become ...... .

Which of the following elements forms $p\pi-p\pi$ bond with itself?