Explain the effect of electron-withdrawing and electron-donating groups on the acidity of carboxylic acids, and provide an example of the increasing acidity order of substituents.

Electron-withdrawing groups (EWG) enhance carboxylic acid acidity by stabilizing the conjugate base through resonance and inductive effects. Examples include halogens or carbonyl groups. In contrast, electron-donating groups (EDG) decrease acidity by destabilizing the conjugate base, as seen with alkyl or aryl groups. The acidity order of substituents can be exemplified by comparing acetic acid (CH₃COOH) to trifluoroacetic acid (CF₃COOH). Trifluoroacetic acid is more acidic due to the electron-withdrawing nature of fluorine, intensifying the resonance stabilization of the conjugate base. This illustrates how substituents’ electronic properties directly impact the acidity of carboxylic acids.