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Variation of Conductance with Dilution

1. Variation of Specific Conductance.

Specific Conductance “К” is the conductance produced by the ions of 1cc of the electrolytic solution. When it is diluted, the concentration of the ions within 1cc volume decreases. Therefore, specific conductance decreases.

Hence, sp. conductance is inversely proportional to dilution.

2. Variation of Equivalent Conductance and Molar Conductance.

Equivalent conductance (λeq) is the conductance furnished by all the ions present in 1 gm equivalent of electrolyte in its solution. Conductance depends upon the no. ions and their speed in the solution.

In weak electrolytes, the degree of ionization increases increasing the density of ions in the solution. Therefore, the equivalent conductance increases.

In strong electrolytes, the no. of ions is the same at all dilution but the ions are more mobile due to a decrease in inter-ionic attraction. As a result, the equivalent conductance increases.

Molar conductance (λm) is the conductance furnished by all the ions present in 1 gm mole of electrolyte in its solution. Molar conductance of both strong and weak electrolytes increases with dilution.

The variation of eq. conductance and molar conductance with dilution is as shown in the graph.