Assertion: Ethanol is weaker acid than phenol.

Reason: Sodium ethoxide may be prepared by the reaction of ethanol with aqueous NaOH.

Assertion is correct but the reason is incorrect.

The correct answer is option 3. Assertion is correct but the reason is incorrect.

Let us delve into the explanation for both the assertion and the reason provided.

Assertion: Ethanol is weaker acid than phenol.

Phenol (C₆H₅OH): When phenol loses a proton (H⁺), it forms the phenoxide ion (C₆H₅O⁻). The phenoxide ion is stabilized by resonance, as the negative charge can be delocalized over the aromatic ring. This delocalization of charge lowers the energy of the ion, making the phenoxide ion more stable and phenol more acidic.

Ethanol (CH₃CH₂OH): When ethanol loses a proton, it forms the ethoxide ion (CH₃CH₂O⁻). The ethoxide ion does not have resonance stabilization, as the negative charge is localized on the oxygen atom. This lack of resonance stabilization makes the ethoxide ion less stable compared to the phenoxide ion, rendering ethanol a weaker acid than phenol.

Thus, phenol is a stronger acid than ethanol due to the resonance stabilization of its conjugate base.

Reason: Sodium ethoxide may be prepared by the reaction of ethanol with aqueous NaOH.

Reaction with Aqueous NaOH: Sodium ethoxide cannot be prepared by the reaction of ethanol with aqueous NaOH. Ethanol is not acidic enough to donate a proton to hydroxide ions (OH⁻) from NaOH. Instead, ethanol reacts with sodium metal to form sodium ethoxide and hydrogen gas.

The reaction for the preparation of sodium ethoxide is:

\(2 \text{C}_2\text{H}_5\text{OH} + 2 \text{Na} \rightarrow 2 \text{C}_2\text{H}_5\text{ONa} + \text{H}_2\)

Inadequate Acid-Base Reaction: For ethanol to react with NaOH, it would need to be a stronger acid than water, which it is not. The pKa of ethanol is around 16, whereas the pKa of water is around 15.7. Since NaOH is a strong base, it prefers to react with stronger acids than ethanol.

The assertion that ethanol is a weaker acid than phenol is correct because phenol's conjugate base is resonance-stabilized, making phenol more acidic.

The reason given is incorrect because sodium ethoxide cannot be prepared by reacting ethanol with aqueous NaOH; instead, it is prepared by reacting ethanol with sodium metal.

Therefore, the correct statement is: Assertion is correct but the reason is incorrect.