(a) A tetratomic molecule `(A)` on reaction with nitrogen `(I)` oxide, produces two substances `(B)` and `( C)` is a dehydrating agent while substance `( C)` is a diatomic gas which shows almost inert behaviour. Identify `(A),(B)` and `( C)`.
(b) Why red phosphorous is denser and chemically less reactive than while phosphorous ?
( c) Why nitrous oxide supports combustion better than air ?

Explanation

(a)`{:(underset("Tetraatomic molecule")((A))+N_(2)Otounderset("Dehydrating agent")((B))+underset("Inert gas")((C))),(underset((A))(P_(4))+10N_(2)Otounderset((B))(P_(4)O_(10))+underset((C))(10N_(2))):}`
`(A)` is tetratomic molecule, which on reaction with nitrogen `(I)` oxide, `N_2 O` gives `(B)`, i.e., `P_4 O_10` which acts as a dehydrating agent, while `( C)` is `N_2`, a diatomic gas which is inert.
(b) Red phosphorous is regarded as a polymer consisting of chains of `P_4` tetrahedra linked together. Hence red phosphorous is denser and less reactive than white phosphorous.
( c) Air has `~ 22 % O_2` in it, while `N_2 O` on decomposition produces `~ 33 %` of `O_2` by volume.
`underset (2 vol.) (2N_2 O) rarr underset (2 vol.) (2 N_2) + underset (1 vol.) (O_2)`
`O_2 = ("Total vol of" N_2 and O_2)/(3) ~~ 33 %`
Since `%` of `O_2` produced by decomposition of `N_2 O` is more, it acts as a better supporter of combustion.