A weak electrolyte salt, AB, dissociates to the ions A + and B - in water. The t
ID: 788720 • Letter: A
Question
A weak electrolyte salt, AB, dissociates to the ions A+ and B- in water. The thermodynamic equilibrium constant, Keqo = 2.0 x 10-8. (a) Calculate the concentration of each ion at equilibrium in a solution that is initially prepared to be 1.0 x 10-4 M in AB, in otherwise pure water.
(b) A diverse, fully dissociated salt is added to the solution in part (a) such that Isolution = 0.10 M. The activity coefficients of A+ and B- are 0.60 and 0.70, respectively, in this solution. Calculate Keq under the new ionic strength condition.
(c) Calculate the % of AB that is dissociated for each condition: part (a) otherwise pure water and part (b) ionic strength = 0.10 M
(d) Comment on the change in dissociation. (Did it increase or decrease? By how much?) Explain the change in amount dissociated.
Explanation / Answer
(a) conc. of each ion= (1*10^-4)^.5= 10^-2= 0.01