Question

The interaction between π bond and lone pair of electrons present on an adjacent atom is responsible for

• A. Resonance effect
• B. Hyperconjugation
• C. Inductive effect
• D. Electromeric effect

Answer 1

The Correct Option is A

The question is about identifying the interaction responsible for the resonance effect among the options given. Let's break this down: 

1. Resonance Effect: This effect occurs when there is a delocalization of π electrons across adjacent atoms in a molecule, facilitated by the overlap of p-orbitals. This effect is often caused by an interaction between a π bond and a lone pair of electrons on an adjacent atom. This leads to the stabilization of the structure by the distribution of electron density over multiple atoms.
2. Hyperconjugation: This is the interaction of σ-bonds (usually C-H or C-C) with adjacent empty or partially filled p or π orbitals to give an extended molecular orbital that increases stability. This does not involve lone pairs and π bonds directly interacting.
3. Inductive Effect: This effect involves the transmission of charge through a chain of atoms in a molecule by electrostatic induction. It relates to the σ-bond framework and not π bonds or lone pairs.
4. Electromeric Effect: This temporary effect occurs in the presence of an attacking reagent, affecting the π bonds but is not the same as the resonance effect. It refers to the temporary transfer of electrons from a double bond or a multiple bond when a reagent attacks.

Given the explanation of each effect, the interaction between a π bond and a lone pair of electrons on an adjacent atom is responsible for the Resonance Effect. Hence, the correct answer is the Resonance Effect.

Answer 2

This interaction is a type of conjugation that leads to resonance, where the π electrons and lone pair electrons interact over adjacent atoms, stabilizing the molecule through delocalization of electrons.
So, the correct answer is : Resonance effect