When concentrated $H_2SO_4$ is heated with $KNO_3$,brown fumes are evolved. These fumes are due to:

The purest form of $N_2$ is prepared by the thermal decomposition of:

When $AgNO_3$ is heated strongly,the products formed are

On passing a gas,$X$,through Nessler's reagent,a brown precipitate is obtained. The gas $X$ is

How can the brown color of $HNO_3$ be removed?

$8 NH_{3} + 3 Cl_{2} \rightarrow X$ (Excess $NH_{3}$)
$NH_{3} + 3 Cl_{2} \rightarrow Y$ (Excess $Cl_{2}$)
What are $X$ and $Y$ in the above reactions?