Posted by darren on .
What are the concentrations of H3O+ and OH- and what is the pH of a 0.15 M solution of Na2CO3 (at 25 °C).
The pH is determined by the hydrolysis of the CO3^-2.
CO3^-2 + HOH ==> HCO3^- + OH^-
Khydrolysis = Kb for carbonate ion = (Kw/K2 for HCO3^-)= (HCO3^-)(OH^-)/(HCO3^-).
Prepare and ICE chart, substitute into the Kb expression above and solve for OH-, pOH, the pH.
[h3o] = 1.78x10 ^-1
[OH] = 5.61x10^-3