NEETChemistryGeneral Organic Chemistry
Which of the following carbocations is the most stable?
Options
- A(CH₃)₃C^+
- BCH₃-O-CH₂^+
- CCH₂=CH-CH₂^+
- D(CH₃)₂CH^+
Correct answer
B. CH₃-O-CH₂^+
Step-by-step solution
The stability of carbocations is determined by the electron-donating effects (resonance, hyperconjugation, and inductive effects) of the attached groups. 1) The tert-butyl cation, (CH₃)₃C^+ , is a 3^ carbocation stabilized by hyperconjugation involving 9 -hydrogens. 2) The methoxymethyl cation, CH₃-O-CH₂^+ , is stabilized by the +M (resonance) effect of the oxygen atom. The lone pair on oxygen is donated to the empty p-orbital of the carbocation, forming a pi bond ( CH₃-O^+=CH₂ ). This completes the octet of every