The percent dissociation of acetic acid in a 0.50 M acetic acid solution is approximately 0.0022%, calculated using the equilibrium concentration of dissociated acetic acid.
The percent dissociation of acetic acid in a solution that is 0.50 M acetic acid and 0.10 M sodium acetate can be found using the equilibrium constant for acetic acid (Ka) and the molarity of the acetic acid and its conjugate base. The Ka value for acetic acid is 1.8 × 10-5. To approximate the percent dissociation, we can use the Henderson-Hasselbalch equation to find the pH of the solution and then use the pH to find the concentration of the dissociated hydrogen ions (H+). However, from the reference material, it seems a specific value for the dissociation concentration of acetic acid was provided as [CH3CO2H] = 1.1 × 10-5 M. Assuming this concentration reflects the equilibrium condition, the percent dissociation (α) can be calculated as follows:
α = ([CH3CO2H] dissociated / [CH3CO2H] initial) × 100%
α = (1.1 × 10-5 M / 0.50 M) × 100%
α ≈ 0.0022%
Therefore, the percent dissociation of acetic acid in this solution is approximately 0.0022%, considering two significant figures as requested.