An element $(X)$ forms compounds of the formula $XCl_3$,$X_2O_5$ and $Ca_3X_2$,but does not form $XCl_5$. Which of the following is the element?

Given below are two statements:
Statement $I$: The $N-N$ single bond is weaker and longer than the $P-P$ single bond.
Statement $II$: Compounds of group $15$ elements in $+3$ oxidation state readily undergo disproportionation reactions.
In the light of the above statements,choose the correct answer from the options given below:

Consider the following molecules $NH_3, PH_3, AsH_3, SbH_3$. Which of the following has the highest boiling point?

Nitrogen forms how many oxides?

Which among the following is non-poisonous in nature?

Which of the following oxides is paramagnetic?