Anomalous Conductance in Electrolyte Solutions: A Potentiometric and Conductometric Study of the Dissociation of Moderately Strong Acids

Properties of the associated forms of five moderately strong acids in aqueous solution (trichloro-, trifluoro-, chlorodifluoro-, and dichloroacetic acids) and sulfamic acid are studied by potentiometric and conductometric methods. Conductometric estimates of the acidity constants for the haloacetic acids are substantially different from the pH potentiometric values. However, the conductometric and pH potentiometric estimates of the acidity constants for sulfamic acid are in agreement. We interpret these results in terms of a neutral associated acid species of each of the haloacids which contributes to the electrolytic conductance.