Question

In the following graph, stability of above carbocations have been shown:

Match the potential energy curve with carbocation.

• A. $\begin{array}{cccc}& \text{I}& \text{II}& \text{III}\\ \text{(b)}& \text{B}& \text{A}& \text{C}\end{array}$
• B. $\begin{array}{cccc}& \text{I}& \text{II}& \text{III}\\ \text{(c)}& \text{C}& \text{B}& \text{A}\end{array}$
• C. $\begin{array}{cccc}& \text{I}& \text{II}& \text{III}\\ \text{(a)}& \text{A}& \text{B}& \text{C}\end{array}$
• D. $\begin{array}{cccc}& \text{I}& \text{II}& \text{III}\\ \text{(d)}& \text{C}& \text{A}& \text{B}\end{array}$

Answer 1

The correct option is B $\begin{array}{cccc}& \text{I}& \text{II}& \text{III}\\ \text{(c)}& \text{C}& \text{B}& \text{A}\end{array}$

I is the most stable carbocation due to dancing resonance. II is aromatic compound and hence more stable than III.
Hence stability order is: $I>II>III$
The larger the stability, the smaller the potential energy (P.E.).