Question

Which of the following statements are TRUE?
(I) Inductive effect operates through the sigma bond
(II) Resonance effect operates through the pi bond
(III) Inductive effects operate through the pi bond
(IV) Resonance effect operates through the sigma bond

• A. (I) and (II)
• B. (II) and (III)
• C. (III) and (IV)
• D. (I) and (IV)

Hint:

The inductive effect moves sigma electrons, while the resonance effect moves pi electrons.

Answer 1

The Correct Option is A

Step 1: Recall what each effect moves.
Inductive effect: pull of sigma electron density along saturated bonds. Resonance effect: delocalisation of pi electrons or lone pairs in conjugation.

Step 2: Judge the four statements.
(I) sigma for inductive: correct. (II) pi for resonance: correct. (III) inductive through pi: incorrect. (IV) resonance through sigma: incorrect.

Step 3: Match.
Only the pair (I) and (II) is made of correct statements, so (A).

Final Answer:
Option (A) is correct. \[ \boxed{\text{(I) and (II)}} \]