Phosphine is produced by adding water to

$A$ pure sample of nitrogen is prepared by heating

The total number of compounds having at least one bridging oxo group among the molecules given below is. . . . . . .
$N_2O_3, N_2O_5, P_4O_6, P_4O_7, H_4P_2O_5, H_5P_3O_{10}, H_2S_2O_3, H_2S_2O_5$

At what temperature is red phosphorus heated to obtain $\alpha$-black phosphorus (in $K$)?

$Assertion :$ Nitrogen and oxygen are the main components in the atmosphere but these do not react to form oxides of nitrogen.
$Reason :$ The reaction between nitrogen and oxygen requires high temperature.

With excess of water,$PCl_5$ gives