The measurement of the electrical conductivity of a solution is known as the conductometry.
The current flow through the conductor is called conductance.In others words it is defined as the reciprocal of the resistance.
The unit for the conductance is seimens (s).
Principle of conductometry :
In this method the main principle is the movements of the ions creates the electrical conductivity.The movements of the ions is depends on the concentration of ions.
Theory of conductometry:
The theory is mainly based on Ohm’s law which states that the current(I) is directly proportional to the electromotive force(E) and inversely proportional to the resistance (R) of the conductor.
I = E/R
Factors effecting the Conductance measurement:
- Temperature:Conductivity of the electrolytes increases with increase in temperature because of the ions mobility by the increasing temperature.
- Concentration of the sample solution: The concentration of the solution, is inversely proportional to the conductivity of the sample solution. The conductance is decrease with increase in the concentration. Hence, the diluted solution are use for the conductivity measurement.
- Number of ions present in the sample solution: This is based on the dissociation of compound into ions. That is mainly of the number of ions present in the solution. The number of ions present in the solution is directly proportional to the conductance. Strong electrolytes completely dissociates into ions and have high conductance.
- Charge of the ions: The negative charge of the ions increase increase the conductivity,Where positive charged ions decrease the conductivity.
- Size of the ions:The conductivity is inversely proportional to the size of the ions.The increase in the size increase the conductivity.
Application of Conductometry:
- The Conductometry is use in the determination of the basicity of the acids. The basicity is defined as the number of carboxylic acid groups attached to the molecules.
- Use in the determination of the springily soluble salts such as barium sulfate and lead sulfate.
- It is use in the determination of the purity of water.
- The determination of the salinity of the sea water.
- It is use in the determination of the ionic product of the water.
- Also use in the quantitative analysis of the compound.