Acetic acid is a weak acid that dissociates into the acetate ion and a proton in aqueous solution: HC₂H₃O₂ (aq) C₂H₃O₂^- (aq) + H⁺ (aq)
At equilibrium at 25 °C a 0.100 M solution of acetic acid has the following concentrations: [HC₂H₃O₂] = 0.0990 M, [C₂H₃O₂^-] = 1.33 × 10^-3 M, and [H⁺] = 1.33 × 10^-3 M. The equilibrium constant, K_eq, for the ionization of acetic acid at 25°C is __________.

Question

Acetic acid is a weak acid that dissociates into the acetate ion and a proton in aqueous solution: HC₂H₃O₂ (aq)

Acetic acid is a weak acid that dissociates into the acetate ion and a proton in aqueous solution: HC<sub>2</sub>H<sub>3</sub>O<sub>2</sub> (aq) C<sub>2</sub>H<sub>3</sub>O<sub>2</sub><sup>-</sup> (aq) + H<sup>+</sup> (aq) At equilibrium at 25 °C a 0.100 M solution of acetic acid has the following concentrations: [HC<sub>2</sub>H<sub>3</sub>O<sub>2</sub>] = 0.0990 M, [C<sub>2</sub>H<sub>3</sub>O<sub>2</sub><sup>-</sup>] = 1.33 × 10<sup>-3</sup> M, and [H<sup>+</sup>] = 1.33 × 10<sup>-3</sup> M. The equilibrium constant, K<sub>eq</sub>, for the ionization of acetic acid at 25°C is __________. A) 5.71 × 10<sup>4</sup> B) 0.100 C) 1.75 × 10<sup>-7</sup> D) 1.79 × 10<sup>-5</sup> E) 5.71 × 10<sup>6</sup>

C₂H₃O₂^- (aq) + H⁺ (aq)
At equilibrium at 25 °C a 0.100 M solution of acetic acid has the following concentrations: [HC₂H₃O₂] = 0.0990 M, [C₂H₃O₂^-] = 1.33 × 10^-3 M, and [H⁺] = 1.33 × 10^-3 M. The equilibrium constant, K_eq, for the ionization of acetic acid at 25°C is __________.

Quizplus · Accepted Answer

The equilibrium constant expression for the ionization of acetic acid is: K_eq = ([C₂H₃O₂^-][H⁺])/[HC₂H₃O₂] Substituting the provided equilibrium concentrations gives: K_eq = ((1.33 × 10^-3)2)/(0.0990) = 1.79 × 10^-5 Therefore, the correct answer is option D.

Acetic Acid Is a Weak Acid That Dissociates into the Acetate