Find the pH and percent ionization of a 0.100 M solution of a weak monoprotic acid having the given Ka values. a. Ka = 1.0 * 10-5 b. Ka = 1.0 * 10-3 c. Ka = 1.0 * 10-1

The acid dissociation constant (Ka) is a quantitative measure of the strength of an acid in solution. It represents the equilibrium constant for the ionization of the acid, which can be defined for a weak monoprotic acid HA in water as follows:

*Ka* = \([H_3O^+][A^-] / [HA]\)

The higher the value of *Ka*, the greater the degree of ionization of the acid at equilibrium, indicating a stronger acid. For instance, a *Ka* value of 1.0 * 10^-1 indicates a stronger acid than one with *Ka* values of 1.0 * 10^-3 or 1.0 * 10^-5. In the context of the exercise, the *Ka* helps us understand how the acid behaves when it dissolves in water and sets the stage for calculating the pH and percent ionization.

An ICE table, which stands for Initial, Change, and Equilibrium, is a systematic way to calculate the changes in concentration of reactants and products over the course of a reaction reaching equilibrium. For ionization of a weak acid, the concentrations are set up as follows:

Initial concentrations are given, the change in concentration for products and reactants is represented by x, and the equilibrium concentration combines the initial concentration and changes. The process involves setting up the equation with the acid dissociation constant and solving for x, which stands for the concentration of ions produced at equilibrium. Simplifications like assuming initial concentration of H3O+ to be negligible aids in solving for x without significant loss of accuracy, especially for weak acids.

Percent ionization is the fraction of the initial amount of acid that has been ionized in solution, expressed as a percentage. It is an indicator of the extent to which an acid dissociates into its ions in water. This can be calculated using the formula:

Percent Ionization = (\([H_3O^+]_{equilibrium} / [HA]_{initial}\)) * 100%

For a 0.100 M solution of a weak monoprotic acid, this calculation provides insight into the efficiency of the ionization process. A higher percent ionization suggests a stronger acid, since more of the original acid has formed ions.

Equilibrium concentration refers to the concentration of reactants and products in a reaction mixture when the forward and reverse reaction rates are equal, causing no net change in concentration over time. It's reached once the system is in equilibrium. To find the equilibrium concentration using the ICE table approach, you use the initial concentrations and the change in concentrations (represented by x) to calculate the final concentrations of H3O+, A-, and the remaining HA in solution. From the exercise, equilibrium concentrations are vital for determining both the pH of the solution and the percent ionization.

Monoprotic acid ionization refers to the dissociation process of acids that have only one ionizable hydrogen atom per molecule. When a monoprotic acid dissolves in water, it transfers this single proton (H+) to a water molecule, forming the hydronium ion (H3O+). The degree of ionization of these types of acids can vary greatly depending on the strength of the acid, which is reflected in the *Ka* value. Demonstrating the ionization of a monoprotic acid through a balanced chemical equation and an ICE table as shown in the steps of the solution, allows for a clear understanding of the acid's behavior in aqueous solutions and is essential for pH and percent ionization calculations.