Chemistry - GOC Question with Solution | TestHub

(i) The oxygen lone pair is donated to the carbon, so every atom has an octet (an oxocarbenium ion): the most stable.

(ii) The benzyl cation is stabilised by resonance with the ring.

(iii) The ethyl cation is a primary cation stabilised only by hyperconjugation.

(iv) The vinyl cation has the positive charge on an sp carbon with an empty p orbital at right angles to the π bond; it cannot be stabilised and is the least stable.

Order: i $>$ ii $>$ iii $>$ iv. So (A) is correct, and (C) (a part of the same order) is also correct. (B) and (D) put the cations in the wrong order.

Answer: (A), (C).