When dissolved in water, CH₃COOH is called acetic acid. Write the equilibrium for its reaction in water and identify the conjugate acid2base pairs.

Strategy Because acetic acid is behaving as a Brønsted–Lowry acid, it will require some species to accept a proton. Here the proton acceptor is water, as is often the case. This allows us to write the equilibrium for the CH₃COOH solution. Once it is written, we identify the conjugate pairs by noting which species differ by only the addition or subtraction of a proton.