Conductivity becomes equal to molar conductivity when 1 cm3 of the solution placed between two large electrodes of 1 cm2 area of cross-section lying 1 cm apart contains 1 mole of electrolyte.
Molar conductivity is the conductance property of a solution containing one mole of the electrolyte. It is a function of the ionic strength of a solution or the concentration of salt. In general, the molar conductivity of an electrolytic solution is the conductance of the volume of the solution containing a unit mole of electrolyte that is placed between two electrodes of unit area cross-section or at a distance of one centimetre apart.
The following expression is used to represent molar conductivity mathematically.
- Λm = K / C
- K is the specific conductivity, and c is the concentration in mole per litre.
The conductivity of a solution is equal to the conductance of a 1 cm length and cross-section area of 1 square cm. it may also be defined as the conductance of a one-centimetre cube of the conductor.
It is represented by the symbol Kappa (κ). mathematically we can write
- κ = 1/ p
- ρ is resistivity
- The conductivity, κ, of an electrolytic solution depends on the concentration of the electrolyte, nature of solvent and temperature.