Solveeit Logo
Login

Question

Chemistry Question on Organic Chemistry- Some Basic Principles and Techniques

Which amongst the following is the most stable carbocation?

A

B

C

+CH3^{CH_3}_{+}

D

CH3  CH3+CH_3 \, \, _{CH_3}^{+}

Answer

Explanation

Solution

The most stable carbocation is t-alkyl carbocation because the order of stability of alkyl carbocation is t-alkyl >s-alkyl> p-alkyl *> CH3 carbocation. This stability order is described with the help of hyperconjugation and inductive effect. On the basis of hyperconjugation, (CH3)2  CH+_3)_2 \, \, ^{+}_{CH} CH shows six resonating structures due to the presence of six a-C - H bonds, Greater the α\alpha H-atom greater will be the hyper conjugation resonating structure and therefore, greater will be the stability. CH3+^{+}_{CH_3}does not show the property of resonance while CH3− +CHCH_3 - \, ^{+}{CH}shows three resonating structures due to presence of three a-C - H bonds. Hence, larger number of resonating structures are possible in (b), so it is most stable. The above order of stability is also explained with the help of (+) /-effect of -CH3_3 group. More the number of - CH3_3 group more will be tendency to displace the electrons towards positive charged carbon of carbocation. Thus, positive charge is decreased or compensated and stability of carbocation is increased.