See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

**Analysis of Carbocation Stability** Carbocation stability depends on **hyperconjugation** and **inductive effects** from alkyl groups. The order is: $$\text{Tertiary} > \text{Secondary} > \text{Primary} > \text{Methyl}$$ **Evaluating each option:** **(A) $CH_3CH_2^{\oplus}$ (Primary carbocation)** - Only one alkyl group attached to the positive carbon - Minimal hyperconjugation and inductive stabilization **(B) $CH_3C(=O)^{\oplus}$ (Acylium ion)** - Resonance with oxygen reduces positive charge density - However, oxygen is electronegative and withdraws electron density - Less stable than a simple alkyl carbocation **(C) $CH_3-C(=NH)^{\oplus}$ (Iminium ion)** - Nitrogen (less electronegative than oxygen) provides resonance - Still has electron-withdrawing effect, reducing overall stability **(D) $(CH_3)_2CH^{\oplus}$ (Tertiary carbocation)** - **Three alkyl groups** attached to the positive carbon - Maximum hyperconjugation: 9 C-H bonds available for donation - Greatest inductive stabilization from multiple methyl groups - **Tertiary carbocation is inherently the most stable** **Answer: (D)** is correct because the tertiary carbocation has maximum hyperconjugative stabilization through three alkyl groups donating electron density to the electron-deficient carbon.