NEETChemistryHydrocarbons
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Benzene reacts with excess chlorine in the presence of anhydrous AlCl ₃ to form an aromatic compound, whereas with chlorine in the presence of UV light it forms a non-aromatic compound. Reason (R): Anhydrous AlCl ₃ generates chlorine free radicals which undergo substitution, whereas UV light genera
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- B(A) is correct but (R) is not correct
- CBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- D(A) is not correct but (R) is correct
Correct answer
B. (A) is correct but (R) is not correct
Step-by-step solution
Assertion (A) is correct: Benzene reacts with excess Cl ₂ in the presence of anhydrous AlCl ₃ (dark, cold) to form hexachlorobenzene ( C ₆ Cl ₆ ), which retains the aromatic ring. However, benzene reacts with Cl ₂ in the presence of UV light to form benzene hexachloride ( C ₆ H ₆ Cl ₆ ), which is a saturated, non-aromatic compound. Reason (R) is incorrect: The roles of the reactive intermediates are swapped in the statement. Anhydrous AlCl ₃ is a Lewis acid that generates the chloronium ion ( Cl ^+ ), which is an e