The cyclic cations having the same number of hyperconjugation are :
Choose the correct answer from the options given below :

Solution

Chemistry ma’am · 3 steps

Count the C–H bonds on carbons touching C⁺; each one gives a hyperconjugative structure.

1. What to count. Each C–H bond on a carbon directly bonded to the positive carbon (an α-hydrogen) can overlap with its empty p orbital. So the number of hyperconjugative structures equals the number of α-hydrogens.
2. Where to look. In every cation, C⁺ has three neighbours: the substituent it carries and the two ring carbons beside it. A ring CH₂ gives 2 α-H, but a ring carbon carrying an ethyl group is a CH and gives only 1.

   Cation	Group on C⁺	Two ring neighbours	Total α-H
   A	CH₃: 3	CH (has ethyl): 1, CH₂: 2	6
   B	CH₃: 3	CH₂: 2, CH₂: 2	7
   C	CH₂CH₃: 2	CH₂: 2, CH₂: 2	6
   D	CH₂CH₃: 2	CH (has ethyl): 1, CH₂: 2	5

3. So. A and C both have 6 α-hydrogens, so they have the same number of hyperconjugative structures. B has 7 and D has 5, so the answer is (c).

The idea to keep. Hyperconjugation counts α-hydrogens only: look at every carbon bonded to C⁺. In an ethyl group only the CH₂ counts, and a ring carbon with a substituent has lost one H.

Answer from the NTA final answer key. Solution by PrepWiser.