Question

The most stable carbonium ion is:

• A. $CH_{3}\overset{+}{C}H_{2}$
• B. $C_{6}H_{5}\overset{+}{C}H_{2}$
• C. $C_{6}H_{5}\overset{+}{C}HC_{6}H_{5}$
• D. $C_{6}H_{5}CH_{2}\overset{+}{C}H_{2}$

Answer 1

Answer: (C)

$C_{6}H_{5}\overset{+}{C}HC_{6}H_{5}$

Answer 2

Carbonium ions $\left( C ^{+}\right)$are electron deficient species with sextet of electron. The order of stability of carbonium ion can be explained on the basis of inductive effect. Alkyl group are electron rich or electron donors and bigger is the alkyl group more is its electron donating tendency ( $+I$ effect) $t > s > p >$ methylionium The most stable carbonium ion is $\left( C _{6} H _{5}\right)_{2}\overset{+}{C}H$.