With excess of water,$PCl_5$ gives

$A$ nitrogen oxide that forms "in situ" when dilute $FeSO_4$ is treated with an aqueous solution of nitrate ion and then carefully adding conc. $H_2SO_4$ along the sides of the test tube,is

Which of the following is the formula for metaphosphoric acid?

The number of $P-O-P$ bridges in the structure of phosphorus pentoxide $(P_4O_{10})$ and phosphorus trioxide $(P_4O_6)$ are respectively:

The reddish-brown coloured gas formed when nitric oxide is oxidised by air is

The nitrogen oxide$(s)$ that contain$(s)$ $N-N$ bond$(s)$ is(are):
$A$. $N_2O$
$B$. $N_2O_3$
$C$. $N_2O_4$
$D$. $N_2O_5$