Assertion: When inductive and electromeric effects operate in opposite directions then the inductive effect predominates.

Reason: Inductive effect is complete transfer of a shared pair of electrons to one of the atoms.

• (A) Both assertion and reason are correct and reason is the correct explanation for the assertion.
• (B) Both assertion and reason are correct but reason is not the correct explanation for the assertion.
• (C) Assertion is correct but reason is incorrect.
• (D) Both assertion and reason are incorrect.

To analyze the given statement, we need to look at both the assertion and the reason closely. The assertion claims that when inductive and electromeric effects act in opposite directions, the inductive effect is stronger. The reason provided states that the inductive effect involves a complete transfer of a shared pair of electrons to one atom.

Evaluating the Assertion

The assertion is generally accepted in organic chemistry. When two opposing effects are at play, the inductive effect, which is a permanent effect, often dominates due to its nature of electron withdrawal or donation through sigma bonds.

Understanding the Reason

The reason describes the inductive effect accurately, as it involves the shifting of electron density towards one atom. However, it does not directly explain why the inductive effect would prevail over the electromeric effect in this scenario.

Conclusion on Options

• Option A: Both assertion and reason are correct, and the reason explains the assertion. (Incorrect)
• Option B: Both assertion and reason are correct, but the reason does not explain the assertion. (Correct)
• Option C: Assertion is correct, but reason is incorrect. (Incorrect)
• Option D: Both assertion and reason are incorrect. (Incorrect)

Therefore, the correct choice is (B): Both assertion and reason are correct, but the reason is not the correct explanation for the assertion.