pH and its Determination of Nonaqueous or Partialy Aqueous Solutions and their Applications

Abstract

There are three values in pH of nonaqueous or partialy aqueous solutions, that is to say, (1) the scale of proton activity in each solvent, (2) the scale of proton activity referred to the water scale, and (3) conventional pH. The value of (1) can be measured by using nonaqueous standard solution of the same solvent and it can not refer to that in another solvents. The value of (2) can only be measured in special solutions in which liquid junction potentials between the reference KCl solution are known and the value of (3) is usually measured in practical use. The e.m.f. of the glass electrode behaves in the same manner as the hydrogen elec-trode in nonaqueous solutions. But the asymmretry potential is far different from that in aqueous solutions. To stabilize the liquid junction potential, conventional pH of nonaqueous solutions must be measured by using the special means different from the aqueous solutions.