How would you identify the conjugate acid-base pairs in the equilibrium equation: HC2H3O2 + H2O --> H3O^+ + C2H3O2^-?

1 Answer
Nov 19, 2015

H_3C-C(=O)OH(aq) +H_2O rightleftharpoons H_3C-C(=O)O^(-)(aq) +H_3O^+

Explanation:

The conjugate base of acetic acid is the acetate anion (the parent acid less a proton, H^+), hence H_3C-C(=O)O^(-). The conjugate acid of OH_2 is water plus a proton, i.e. an hydronium ion, H_3O^+. This is a representation, and as far as anyone knows the hydronium ion is a cluster of 3-4 water molecules (say O_3H_6) plus a proton to give H_7O_3^+. To represent the reactivity of this species in aqueous solution, H^+ or H_3O^+, are entirely appropriate shorthands.