Write a balanced chemical equation for the reaction showing catalytic oxidation of $NH_3$ by atmospheric oxygen.

Which of the following compounds is used as a refrigerant?

Which of the following is a good oxidising agent?

The bond energies (in $kJ \ mol^{-1}$) of $N-H$,$P-H$,and $As-H$ are respectively:

The oxide of nitrogen formed by thermal decomposition of $NH_4NO_3$ is

Choose the correct statement$(s)$ among the following.
$A$. $SnCl_2 \cdot 2 H_2O$ is a reducing agent.
$B$. $SnO_2$ reacts with $KOH$ to form $K_2[Sn(OH)_6]$.
$C$. $A$ solution of $PbCl_2$ in $HCl$ contains $Pb^{2+}$ and $Cl^{-}$ ions.
$D$. The reaction of $Pb_3O_4$ with hot dilute nitric acid to give $PbO_2$ is a redox reaction.