Which acid in each of the following pairs has the stronger conjugate base? See Table 16.1 to compare the relative strengths of conjugate acid-base pairs. (a) HCl or HF

Key Concepts

Conjugate Acid-Base Pairs

A conjugate acid-base pair consists of two species that differ by the presence of a proton (H+). When an acid donates a proton, it forms its conjugate base, while the base that accepts the proton becomes its conjugate acid. Understanding these pairs is essential for comparing the strengths of acids and bases, as the strength of an acid is inversely related to the strength of its conjugate base.

Acid Strength and Conjugate Base Strength

The strength of an acid is determined by its ability to donate protons, which correlates with the stability of its conjugate base. A stronger acid has a weaker conjugate base because the conjugate base is less stable and less likely to accept a proton. This relationship is crucial for determining which acid in a pair has the stronger conjugate base by analyzing their relative strengths.

Electronegativity and Bond Strength

Electronegativity refers to the tendency of an atom to attract electrons in a bond. In the context of acids, the electronegativity of the atom bonded to hydrogen affects the bond strength and the stability of the conjugate base. For example, HF has a stronger H-F bond than HCl has in H-Cl, making HF a weaker acid and thus its conjugate base (F-) stronger than that of HCl (Cl-).