Question

Most stable carbocation among the following is :

• A. $(Ph{)}_{2}CH\stackrel{\oplus }{C}{H}_2$
• B. $(Ph{)}_2\stackrel{\oplus }{C}C{H}_3$
• C. $Ph\stackrel{\oplus }{C}{H}_2$
• D. $(C{H}_3{)}_{3}C\stackrel{\oplus }{C}{H}_2$

Answer 1

The correct option is B $(Ph{)}_2\stackrel{\oplus }{C}C{H}_3$

Tertiary carbocation $(Ph{)}_2\stackrel{\oplus }{C}C{H}_3$ is resonance stabilised by two phenyl groups and by hyperconjugation due to three $\alpha$-hydrogens present on methyl group. Hence it is most stable among the given options.