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

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

Which of the following oxides of nitrogen is the anhydride of $HNO_3$?

Which of the following is not correct for $N_2O$?

Assertion : Although $PF_5, PCl_5$ and $PBr_5$ are known,the pentahalides of nitrogen have not been observed.
Reason : Phosphorus has lower electronegativity than nitrogen.

Red phosphorus can be obtained from white phosphorus by: