When ammonia is passed over heated $CuO$,it is oxidised to

The compound$(s)$ which generate$(s)$ $N_2$ gas upon thermal decomposition below $300^{\circ} C$ is (are)
$A. NH_4NO_3$
$B. (NH_4)_2Cr_2O_7$
$C. Ba(N_3)_2$
$D. Mg_3N_2$

Assertion : Molecular nitrogen is less reactive than molecular oxygen.
Reason : The bond length of $N_2$ is shorter than that of oxygen.

How many $P-O-P$ linkages are there in $P_4O_{10}$?

Nitrogen dioxide cannot be prepared by heating:

The number of pentagons in $C_{60}$ and trigons (triangles) in white phosphorus,respectively,are