Why $NH_3$ cannot be dried by $H_2SO_4$,$P_2O_5$,and $CaCl_2$?

Why does nitrogen show catenation properties less than phosphorus?

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

The basicity of orthophosphoric acid $(H_3PO_4)$ is:

Choose the correct statements about the hydrides of group $15$ elements.
$A$. The stability of the hydrides decreases in the order $NH_3 > PH_3 > AsH_3 > SbH_3 > BiH_3$
$B$. The reducing ability of the hydrides increases in the order $NH_3 < PH_3 < AsH_3 < SbH_3 < BiH_3$
$C$. Among the hydrides,$NH_3$ is strong reducing agent while $BiH_3$ is mild reducing agent.
$D$. The basicity of the hydrides increases in the order $NH_3 < PH_3 < AsH_3 < SbH_3 < BiH_3$
Choose the most appropriate from the option given below:

Which statement is not correct for nitrogen?