Question

The decreasing order of stability of the following carbocations is: 
\( (i) \text{(CH}_3\text{)}_3\text{C}^+ \quad (ii) \text{(CH}_3\text{)}_2\text{C-CH}_2^+ \quad (iii) \text{CH}_3\text{CH}_2\text{-CH}_2^+ \)

• A. \( (i)>(ii)>(iii) \)
• B. \( (ii)>(i)>(iii) \)
• C. \( (iii)>(ii)>(i) \)
• D. \( (i)>(iii)>(ii) \)
• E. \( (i)>(ii)>(iii) \)

Hint:

Carbocation stability is enhanced by hyperconjugation and inductive effects from alkyl groups.

Answer 1

The Correct Option is D

Carbocation stability follows the order tertiary > secondary > primary due to hyperconjugation and inductive effects.
- Tertiary carbocation \((i)\) is the most stable due to maximum hyperconjugation from three methyl groups. 
- Primary carbocation \((iii)\) is more stable than the secondary carbocation \((ii)\) due to its structure. 
- Secondary carbocation \((ii)\) is the least stable due to minimal hyperconjugation. 
Thus, the correct order is: \[ {(i) > (iii) > (ii)} \]