The formula of the vapour state of white phosphorus is ......

The decrease in stability of the higher oxidation state in the $p-$block elements with an increasing atomic number is due to:

Small quantities of $NO$ and $HNO_3$ are formed as impurities when $N_2$ is prepared from $NH_4Cl_{(aq)}$ and $NaNO_{2(aq)}$. These impurities can be removed by passing the $N_2$ gas through which of the following?

$HNO_3$ is produced in good yield by which of the following methods?

$A$ nitrogen oxide that forms "in situ" when dilute $FeSO_4$ is treated with an aqueous solution of nitrate ion and then carefully adding conc. $H_2SO_4$ along the sides of the test tube,is

Which of the following does not produce ammonia upon heating?