Given below are two statements :
Statement I : Hyperconjugation is not a permanent effect.
Statement II : In general, greater the number of alkyl groups attached to a positively charged Cation, greater is the hyperconjugation interaction and stabilization of the cation.
In the light of the above statements, choose the correct answer from the options given below

Solution

Chemistry ma’am · 4 steps

Sort the effects into permanent and temporary: only the electromeric effect needs a reagent to switch on.

1. Statement I. Hyperconjugation is the spreading of the σ electrons of a C-H bond into an adjacent empty p orbital or π bond. It is present in the molecule's ground state and changes real properties such as bond lengths and dipole moments, so it is a permanent effect. Statement I is false.
2. The temporary one. The only temporary effect in GOC is the electromeric effect. It appears only when an attacking reagent is present and disappears once the reagent is removed.
3. Statement II. Each alkyl group on the positive carbon brings α C-H bonds that can push electron density into the empty p orbital. More alkyl groups give more α C-H bonds, more hyperconjugative structures and a more stable cation. Statement II is true.

   (CH₃)₃C⁺ > (CH₃)₂CH⁺ > CH₃CH₂⁺ > CH₃⁺

4. So. Statement I is false and Statement II is true, which is option (a).

The idea to keep. Inductive, resonance and hyperconjugation are permanent, ground-state effects. Only the electromeric effect is temporary. For hyperconjugation, count the α C–H bonds: more of them means more stabilisation.

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