Consider the following carbocations: (I) ( CH ₃ )₃ C (II) CH ₂= CH - C H ₂ (III) ( CH ₃ )₂ C H (IV) CH ₂= C H The correct decreasing order of their stability is:

Step-by-step solution

The stability of carbocations depends on resonance, hyperconjugation, and the hybridization of the carbon bearing the positive charge. (I) ( CH ₃ )₃ C (tert-butyl cation) is highly stabilized by hyperconjugation due to 9 -hydrogens. (II) CH ₂= CH - C H ₂ (allyl cation) is stabilized by resonance involving the adjacent bond. (III) ( CH ₃ )₂ C H (isopropyl cation) is stabilized by hyperconjugation from 6 -hydrogens. (IV) CH ₂= C H (vinyl cation) is highly unstable because the positive charge is on an electronegative