Química analítica básica: o comportamento ácido-base em solução aquosa

Abstract

Acetic acid and aqueous ammonia (also erroneously called ammonium hydroxide) are the most common examples mentioned in class when introducing students to concepts and calculations involving acid-base equilibria in aqueous solution. This is because its equilibrium constants allow approximations that simplify calculations without incurring gross errors. But these examples are peculiarities and should not be generalized. And more! How to deal with polyfunctional acids and bases ("polyprotic")? What happens to the dilution of the sample? The answers to these and other questions will be presented in this article with the mathematical equation of the chemical systems, based on the works some authors that are dedicated to equate these problems in a didactic way [1-7]. More specifically, it is intended to highlight and detail the texts presented by Butler [1] in his excellent book "Ionic Equilibrium: a mathematical approach", used as the main focus in this article.