Question

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :
Assertion A : Aryl halides cannot be prepared by replacement of hydroxyl group of phenol by halogen atom.
Reason R : Phenols react with halogen acids violently. In the light of the above statements.
Choose the most appropriate from the options given below:

• A. Both A and R are true but R is NOT the correct explanation of A
• B. A is false but R is true
• C. A is true but R is false
• D. Both A and R are true and R is the correct explanation of A

Answer 1

The Correct Option is C

To determine the correct option, let's analyze both the assertion (A) and the reason (R) provided.

1. Assertion (A): "Aryl halides cannot be prepared by replacing the hydroxyl group of phenol with a halogen atom."
   • Phenols possess a hydroxyl group (\(-OH\)) attached to an aromatic benzene ring.
   • The oxygen atom of the hydroxyl group in phenols forms a resonance-stabilized bond with the benzene ring, resulting in a strong and stable bond.
   • This stability makes it difficult to directly substitute the \(-OH\) group with a halogen atom.
   • Therefore, the assertion is correct.
2. Reason (R): "Phenols react violently with halogen acids."
   • Phenols do not exhibit violent reactions with halogen acids such as HCl, HBr, or HI.
   • Halogen acids typically do not react significantly with phenols under standard conditions, as phenol does not readily undergo substitution reactions when heated with HX acids.
   • Consequently, the reason is incorrect.

Based on the preceding analysis:

• The assertion (A) is true because the direct substitution of the hydroxyl group in phenols with a halogen atom is not feasible due to resonance stabilization.
• The reason (R) is false, as phenols do not react violently with halogen acids like HCl or HBr.

Consequently, the most fitting option, given the statements, is: A is true but R is false.