On mixing two colourless gases,a deep brown colour is observed. The gases are

Assertion: $NO$ and $NO_2$ both are paramagnetic gases.
Reason: $NO$ gas is responsible for the Brown ring test.

In some of the reactions,thallium resembles aluminium,whereas in others,it resembles group $1$ metals. Support this statement by giving some evidence.

The acidic character of the group-$15$ elements' oxides in increasing order is:

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

Extra pure $N_2$ can be obtained by heating :-