Multipurpose ammonium chloride : its possible use as a high-ionic-strength pH-metric standard

PH measurements on high-ionic-strength sample solns., esp. at high acidities or high alkalinities, may be impaired by high residual liq.-junction potentials. To cope with this problem, a refined pH-metric procedures is suggested. It implies the use of CsCl salt bridges, (rather than KCl), together with the adoption of pH stds. having ionic strengths comparable with those of the sample solns., under conductimetric control. A scheme of detn. of high-ionic-strength pHs stds. based on aq. NH4Cl solns. of molalities 0,0534 < m < 7 is described.