When a lightning flash is produced,which gas is primarily formed?

Strong reducing behaviour of $H_3PO_2$ is due to

White phosphorus on heating with concentrated $NaOH$ solution in an inert atmosphere of $CO_2$ gives a salt '$X$' and gas '$Y$'. The oxidation state of central atom in $X$ and $Y$ is respectively

Which reaction does not produce ammonia?

The most acidic among the following compounds is

$PCl_5$ exists but $NCl_5$ does not because