Question

Consider an aqueous solution of 0.140 M 2-oxopropanoic acid (pyruvic acid). a) Write a mass balance and charge balance equation for the solution. b) Comment on the relative concentrations of all the ions.

Answer 1

In a solution of 0.140 M 2-oxopropanoic acid, a mass balance equation and a charge balance equation are created to consider the concentrations of the ions, which will help define whether the solution is acidic, basic, or neutral. The relative concentrations of the ions are determined by the pH of the solution.

Step-by-step explanation:

For a solution of 0.140 M 2-oxopropanoic acid (pyruvic acid), we first perform a mass balance and charge balance to describe the initial states of the solution. The mass balance on pyruvic acid gives us [CH₃COCOOH] = ([CH₃COCOO⁻] + [CH₃COCOOH]). The charge balance equation is [H⁺] = [OH⁻] + [CH₃COCOO⁻]. The relative concentrations of ions in solution largely depend on the degree of ionization and the pH of the solution. According to the Henderson-Hasselbalch equation, the concentration of hydroxide ion or hydronium ion can be calculated, which further gives us the pH of the solution. If the pH is less than 7, the solution is acidic and [H3O+] is higher than [OH-]. If the pH is greater than 7, [OH-] is higher than [H3O+]. If the pH equals 7, [H3O+] equals [OH-].

Learn more about Acid-Base Equilibrium