Ionic Strength of Soluble Salts
Activity Coefficients
pH Revisited

In this section we now include activity coefficients when calculating the pH values of solutions. 

pH Revisited Calculations

Example #1: If at 50 oC the ionization of pure water, Kw, is 7.94 x 10-14 what is the pH of a neutral solution?

a) 7.00

b) 6.55

c) 13.10

d) Since Kw is a constant the number doesn’t change. 

Example #2: What would be the pH of the same pure water when it contains 0.005 M NaBr at 50 oC? 

Example #3: Find the pH of a saturated solution of Barium hydroxide, Ba(OH)2 when dissolved in 0.05 LiNO2. The Ksp of Ba(OH)2 is 5.0 x 10-3