Question

which is more stable:
methoxymethyl cation(CH3OCH2+) or n-propyl cation(CH3CH2CH2+)

Answer 1

methoxy methyl cation is more stable than than n-propyl cation.

It is because the + mesomeric effect of methoxy group stabilizes the positive charge more than the +inductive effect of propyl group as in n-propyl cation.

Mesomeric effect stabilizes more than inductive effect, because +mesomeric effect involves the actual transfer of electrons from a group while +inductive effect involves only the repulsion of electrons from a carbon.

All alkyl groups show + inductive effect.