Question

In which of the following pairs, first structure is more stable than second?

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

(a) $I{I}^{nd}$ structure is more stable than $I^{st}$ because the carbocation formed is stabilised by $+M$ effect of oxygen atom.

(b) $I{I}^{nd}$ structure is more stable than $I^{st}$ because it has more hyperconjugating structures and is a secondary carbocation.

(c) $I^{st}$ structure is more stable than $I{I}^{nd}$ because the carbocation formed is stabilised by $+M$ effect of nitrogen atom and the electron donating ability of nitrogen is more than oxygen.

(d) $I{I}^{nd}$ structure is the more stable than $I^{st}$ because the carbocation is stabilised by dancing resonance.