Benzoic acid (c6h5co2h=HBz) solutions are sometimes used in experiments to determine the molarity of a basic solution of unknown concentration. what is the pH of a 0.100M solution of benzoic acid if ka=6.5x10-5 and the equilibrium equation of interest is : HBz(aq)+h20(l)<--->h3O+(aq)+Bz-(aq).