Question

Which of the following statements regarding different electronic effects in organic reactions is TRUE ?

• A. Hyperconjugation is a temporary electronic effect.
• B. -CN group show positive resonance effect.
• C. The effect of hyperconjugation is usually stronger than the inductive effect.
• D. The resonance hybrid is less stable than any of the resonance structures.

Hint:

Check each statement against the definitions of hyperconjugation, the cyano group effect and resonance stability.

Answer 1

The Correct Option is C

Step 1: Elimination Route
The temporary effect is the electromeric effect, so (A) is out.

Step 2: More Eliminations
The cyano group withdraws electrons by resonance, so it shows a -R effect, which rules out (B). The hybrid is lower in energy than any contributor, which rules out (D).

Step 3: Result
Only (C) remains, option (C).

Final Answer:
Only the statement about hyperconjugation is true. \[ \boxed{\text{(C) }\text{The effect of hyperconjugation is usually stronger than the inductive effect.}} \]