Question

Question: Rank the following carbocations in order of increasing stability.

a.

b.

c.

Short answer

ANSWER

The order of increasing stability is :$\mathrm{a}<\mathrm{b}<\mathrm{c}$

Step-by-step solution

Carbocations

Carbocations are the ionic species that contain a positive charge on the carbon atom.

Stability of carbocations

The factors affecting the stability of the carbocations are as follows:

• Multiple bonds: A double or a triple bond adjacent to the carbocations impart exceptional stability to the carbocation.

• Hyperconjugation: The stability order of the carbocation increases in the manner CH₃⁺$1°<2°<3$

• Lone pairs on adjacent carbon atom to the carbocationic center provide stability to the carbocation.

Determination of the order of increasing stability

a. Vinyl carbocations are very less stable, even less than the primary carbocations. Hence, (a) is least stable among the given carbocations.

b. The given compound is a secondary carbocation. Hence, it is the most stable among the given compounds.

c. Given is the primary carbocation. It has intermediate stability (more than the vinyl carbocations).

Hence, the order of increasing stability is $\mathrm{a}<\mathrm{b}<\mathrm{c}$.