Which among the following group $15$ elements does not exhibit allotropy?

White phosphorus,when heated with conc. $NaOH$ solution in an inert atmosphere of $CO_2$,forms phosphine and a sodium salt of oxoacid of phosphorus,$'X'$. The oxidation state of phosphorus in $'X'$ is

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

The reaction that does not produce nitrogen is

Which of the following oxides does not form an acidic aqueous solution?

What is the product formed when white phosphorus reacts with thionyl chloride $(SOCl_2)$?