Which of the following compounds will not give $NH_3$ on heating?

At high temperatures,nitrogen directly combines with

The atomic number of $N$ is $7$. The atomic number of the $3$rd member of the nitrogen family is:

Which of the following fluorides does not exist?

The products formed during thermal decomposition of ammonium dichromate are

Identify the reactions in which $N_2$ is liberated.
$a. \ (NH_4)_2SO_4 + NaOH \longrightarrow$
$b. \ NH_3 + Cl_2 \longrightarrow$ (excess $Cl_2$ is not specified, but $N_2$ is formed when $NH_3$ is in excess)
$c. \ (NH_4)_2Cr_2O_7 \xrightarrow{\Delta}$
$d. \ NH_4NO_3 \xrightarrow{\Delta}$
$e. \ NH_4Cl_{(aq)} + NaNO_{2_{(aq)}} \longrightarrow$