NEETChemistryAlcohols Phenols and Ethers
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Chlorobenzene cannot be converted to phenol by boiling with aqueous NaOH at standard temperature and pressure. Reason (R): In chlorobenzene, the C - Cl bond acquires a partial double bond character due to resonance, making it difficult to cleave. In the light of the above statements, choose the mos
Options
- ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- BBoth (A) and (R) are correct and (R) is the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
B. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
Assertion (A) is correct. Aryl halides like chlorobenzene are extremely less reactive towards nucleophilic substitution reactions under normal conditions. The conversion of chlorobenzene to phenol (Dow's process) requires drastic conditions: 623 K temperature and 300 atm pressure. Reason (R) is also correct and explains the Assertion. In chlorobenzene, the lone pair of electrons on the chlorine atom is in conjugation with the pi-electrons of the benzene ring. This resonance imparts a partial double bond character t