Determination of the activity coefficient by a conductivity measurement with CobraSMARTsense

Principle

The equivalent conductivity of strong electrolytes depends on their concentration. The quotient of the equivalent conductivity at a certain concentration and the equivalent conductivity at infinite dilution is called the conductivity coefficient, which is the result of interionic action.

Benefits

• Entrance to the world of datalogging by using the Cobra4 Mobile-Link
• Stable and safe construction due to solid stand material

Tasks

1. Measure the specific conductivities of various potassium chloride and calcium chloride solutions and calculate the equivalent conductivities.
2. Determine the equivalent conductivities at infinite dilution using the Kohlrausch equation and calculate the conductivity coefficients.

Learning objectives

• Equivalent conductivity
• Ion mobility
• Conductivity
• Interionic action

Necessary accessories

• Analytical balance 120g/0.1mg