Which product is formed by the reaction of $Zn$ with cold and very dilute $HNO_3$?

The statement true for $N_3^-$ is

$A$ colourless gas with the smell of rotten fish is

Which is the correct statement for the given acids?

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.

Pure $N_2$ is not produced when