QS Study

Applications of Conductance Measurements

Conductance of electrolytes depends on the number of ions and their speeds. The measurements of conductance of electrolytic solutions have been utilized for determining –

(a) the end points of acid-base titrations,

(b) the end points of precipitation titrations;

(c) the solubility of sparingly soluble salts and

(d) the kinetics of reactions.

For conductometric titration experiments a known volume of the solution to be titrated is placed in a beaker and a conductivity cell dipped into it. The conductivity cell is now connected to one end of the Wheatstone’s bridge. The other solution is then added to the solution in the beaker in installments and the conductance measured after each addition. This is continued beyond a sharp change in conductance value. The conductance values are then plotted against the volumes of titrated added. In each case the straight line portions of the graph are extrapolated and the point at which the straight lines intersect is taken as the end pony of the titration.

Common Application of conductance measurements:

  • Determination of dissociation constant of weak electrolyte from conductance measurements.
  • Weak electrolyte like HAc dissociation in according to: Determination the solubility of a sparingly soluble salt by conductance measurement.

Conductance offers a very simple and convenient mean for determining the solubility of a sparingly soluble salt such as AgCl, , etc. dissolved in to a very small extent. That is why these salts are called sparingly soluble salts.