The Basis of Conductometric Titrations

The Basis of Conductometric Titrations:

The addition of an electrolyte to a solution of another electrolyte under conditions producing no appreciable change in volume will affect the conductance of the solution according to whether or not ionic reactions occur.If no ionic reaction take place,such as in the addition of one simple salt to another(KCl,NaNO3) the conductance will simply rise.If ionic reaction occurs, the conductance may either increase or decrease:thus in the addition of a base to a strong acid ,the conductance decrease owing to the replacement of the hydrogen ion of high conductivity by another cation of lower conductivity,This is the principle underlying conductimetric titration i.e:the substitution of ions of one conductivity by ions of another conductivity
During the progress of neutralization changes in conductivity may in general be expected, and these may therefore be employed in determining the end points as well as the progress.
Of the reactions.The reaction conductivity is measured after each addition of a small volume of the reagent, and the points thus obtained are plotted to give a graph which consists of two straight lines intersecting at the equivalence point,The accuracy of the method is greater the more acute the angle of intersection and more nearly the points of the graph lie on a straight line