Question

Arrange the following in increasing order of acid strength: phenol, ethanol, water.

Hint:

Acidity increases with the stabilization of the conjugate base. Resonance structures, like in phenol, increase the acid strength by stabilizing the conjugate base.

Answer 1

To arrange phenol, ethanol, and water in increasing order of acid strength, we need to look at their ability to donate a proton (H\(^+\)). The greater the ability to donate a proton, the stronger the acid: - Phenol is a weak acid, but it is stronger than ethanol due to the resonance stabilization of the phenoxide ion after deprotonation. - Ethanol is weaker than phenol as the ethoxide ion is less stabilized than the phenoxide ion. - Water is the weakest acid because it does not have any resonance stabilization after losing a proton. Thus, the order of increasing acid strength is: \[ \text{Ethanol}<\text{Water}<\text{Phenol} \]