Inductive effects:

Stabilizing the conjugate base's negative charge is significant in determining the strength of the acid and thus any influence that stabilizes the charge will result in a stronger acid. Substituents can assist to stabilize a negative charge and do so through an inductive effect. This is demonstrated by comparing the pK_a values of the alcohols CF₃CH₂OH and CH₃CH₂OH (12.4 and 16, correspondingly) in which CF₃CH₂OH is more acidic than CH₃CH₂OH. This implies that the anion CF₃CH₂O is more stable as compared to the CH₃CH₂O .

Figure (a) 2 ,2, 2-Trifluoroethoxy ion; (b) ethoxy ion.