Question

Given below are two statements Statement-I: Phenol is acidic due to resonance stabilization of phenoxide ion. Statement-II: Phenol has no reaction with \(\mathrm{Na_2Cr_2O_7}\) and concentrated \(\mathrm{H_2SO_4}\). The correct answer is

• A. Both statements I and II are correct
• B. Statement I is correct but statement II is not correct
• C. Statement I is not correct but statement II is correct
• D. Both statements I and II are not correct

Hint:

Phenol is acidic because \[ \boxed{\text{phenoxide ion is resonance stabilized}.} \] Also, \[ \boxed{\text{Phenol is readily oxidized to quinones by strong oxidizing agents.}} \]

Answer 1

The Correct Option is B

Step 1: Examine Statement-I. Phenol is more acidic than alcohols because the phenoxide ion formed after the loss of a proton is resonance stabilized. \[ \boxed{ \mathrm{C_6H_5OH \rightleftharpoons C_6H_5O^- + H^+} } \] The negative charge on the oxygen atom is delocalized over the aromatic ring through resonance. Hence, \[ \boxed{\text{Statement-I is correct}.} \]

Step 2: Examine Statement-II. Phenol reacts with acidified sodium dichromate \[ \left(\mathrm{Na_2Cr_2O_7/H_2SO_4}\right) \] and gets oxidized to quinones. Therefore, the statement that phenol has no reaction with \[ \mathrm{Na_2Cr_2O_7} \] and concentrated \[ \mathrm{H_2SO_4} \] is incorrect. Hence, \[ \boxed{\text{Statement-II is not correct}.} \]

Step 3: Choose the correct option. Therefore, \[ \boxed{\text{Statement-I is correct but Statement-II is not correct}.} \] Hence, the correct option is \(\boxed{(B)}\).