Question

What is the wheatstone bridge’s significance in the determination of the conductivity of a solution?

Answer 1

1. The wheatstone bridge is significant in determining the conductivity of a solution because it allows for accurate measurement of the electrical resistance of the solution in a conductivity cell.
2. Conductivity itself cannot be measured directly; instead, it is calculated from resistance using the relation
   `kappa = K/R`​
   Here, κ is the specific conductivity,
   K is the cell constant, and
   R is the resistance measured using the wheatstone bridge.
3. In the setup, the unknown resistance of the electrolyte solution is placed in one arm of the bridge. When the bridge is balanced, the resistance can be precisely determined. Since electrolyte solutions often have low conductance, the wheatstone bridge provides a sensitive and reliable method to detect small changes in resistance.
4. Additionally, AC current is used in modern bridges to prevent polarisation of electrodes and avoid electrolysis, ensuring consistent and accurate readings. This method is widely used in conductometric titrations and studies of electrolytic behaviour.