Question

What is the stability order of carbocations?

• A. Primary \(>\) Secondary \(>\) Tertiary
• B. Secondary \(>\) Primary \(>\) Tertiary
• C. Tertiary \(>\) Secondary \(>\) Primary
• D. Primary \(>\) Tertiary \(>\) Secondary

Hint:

More alkyl groups attached to a carbocation increase its stability due to hyperconjugation and the +I inductive effect.

Answer 1

The Correct Option is C

Concept: Carbocations are positively charged carbon species formed during many organic reactions. Their stability depends mainly on the inductive effect and hyperconjugation provided by surrounding alkyl groups.

Step 1: Understanding stabilization by alkyl groups. Alkyl groups donate electron density through the \(+I\) (inductive) effect and hyperconjugation, which helps stabilize the positive charge on carbon.

Step 2: Comparison of carbocations.
• Tertiary carbocation – attached to three alkyl groups (most stable).
• Secondary carbocation – attached to two alkyl groups.
• Primary carbocation – attached to one alkyl group (least stable).

Step 3: Conclusion. Hence, the stability order of carbocations is: \[ \text{Tertiary}>\text{Secondary}>\text{Primary} \]