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

What is the lowest oxidation state possessed by phosphorus in its oxyacids?

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:

Nitrous oxide $(N_2O)$ is:

Which oxide of nitrogen is obtained on heating ammonium nitrate at $250 \, ^oC$?

Which of the following oxoacids of phosphorus has the lowest oxidation state of phosphorus?