Question

Which of the following carbocation is most stable?

(a)$(C{H}_3{)}_{3}C-C{H}_2^{+}$ (b) $(C{H}_3{)}_3{C}^{+}$ (c) $C{H}_{3}C{H}_{2}C{H}_2^{+}$ (d) $C{H}_{3}C{H}^{+}C{H}_{2}C{H}_3$

Answer 1

• The hyperconjugation involves the delocalisation of sigma electrons to the empty p orbital present at the alpha position as shown in the above image.
  
• Hence, there is need of a sigma $C-H$ bond of the $s{p}^3$ hybridized carbon atom which is present at alpha position with respect to the carbocation.
  
• More the number of sigma $C-H$ bonds at alpha position, more the number of hyperconjugating structures and more the stability. Hence structure (b) which is having nine sigma $C-H$ bonds will be the most stable carbocation.