Give one word or phrase for hydrocarbons containing a $\overset{\underset{\text{||}}{\text{O}}}{\text{-C-}}$ functional group

Give reasons for:

(i) Methane does not undergo addition reactions, but ethene does.

(ii) Ethyne is more reactive than ethane.

(iii) Hydrocarbons are excellent fuels.

Ethanol reacts with sodium to give …………… [sodium ethanoate, sodium ethoxide, sodium propanoate]

Give the structural formulae for :

(i) An isomer of n-butane.

(ii) 2-propanol.

(iii) Diethyl ether.