Consider a solution prepared by mixing a weak acid HA, HCl, and NaA. Which of the following statements best describes what happens? a. The \(\mathrm{H}^{+}\) from the HCl reacts completely with the \(\mathrm{A}^{-}\) from the NaA. Then the HA dissociates somewhat. b. The \(\mathrm{H}^{+}\) from the HCl reacts somewhat with the \(\mathrm{A}^{-}\) from the NaA to make HA, while the HA is dissociating. Eventually you have equal amounts of everything. c. The \(\mathrm{H}^{+}\) from the HCl reacts somewhat with the \(\mathrm{A}^{-}\) from the NaA to make HA while the HA is dissociating. Eventually all the reactions have equal rates. d. The \(\mathrm{H}^{+}\) from the HCl reacts completely with the \(\mathrm{A}^{-}\) from the NaA. Then the HA dissociates somewhat until "too much" \(\mathrm{H}^{+}\) and \(\mathrm{A}^{-}\) are formed, so the \(\mathrm{H}^{+}\) and \(\mathrm{A}^{-}\) react to form HA, and so on. Eventually equilibrium is reached. Justify your choice, and for choices you did not pick, explain what is wrong with them.

Before analyzing each statement, it is important to understand some basic concepts: 1. In a solution containing a weak acid HA, the primary reaction is: HA ↔ H⁺ + A⁻ (Where ↔ indicates that the reaction is in equilibrium) 2. HCl is a strong acid, which will completely dissociate in solution: HCl → H⁺ + Cl⁻ (Where → indicates a complete reaction) 3. NaA is a salt containing the conjugate base A⁻. In solution, the salt will dissociate as well: NaA → Na⁺ + A⁻ With these reactions in mind, we can now analyze the given statements and determine which one is correct.

a. This statement says that H⁺ from HCl will react completely with A⁻ from NaA, and then HA will dissociate. This scenario is incorrect, because H⁺ ions from HCl and HA will compete for the A⁻ ions from NaA. The reaction will continue until equilibrium is reached. b. This statement suggests that H⁺ from HCl will react with A⁻ from NaA to form equal amounts of HA, H⁺, and A⁻. This is incorrect, as the reaction will not result in equal amounts of each species. The ratio of the species in the solution at equilibrium will depend on the equilibrium constant of the weak acid and the initial concentrations of all species. c. This statement explains that both HA dissociation and H⁺ from HCl reacting with A⁻ from NaA happen at the same time, and eventually, all reactions have equal rates. This is the correct statement because in a mixture of strong and weak acids, both reactions will support each other until equilibrium is reached. d. According to this statement, H⁺ from HCl reacts completely with A⁻ from NaA, then HA dissociates until "too much" H⁺ and A⁻ are formed, and H⁺ and A⁻ react to form HA again. This statement is incorrect because it oversimplifies the actual process happening in the solution. The H⁺ from HCl and the dissociation of HA will influence the reaction at the same time until equilibrium is reached.

The correct statement is (c). The H⁺ from HCl reacts somewhat with the A⁻ from NaA to make HA while the HA is dissociating. Eventually, all the reactions have equal rates. Statements a, b, and d are incorrect because they do not correctly describe the behavior of the acids and their impact on the equilibrium of the system.