Conductivity of strong and weak electrolytes (with the Cobra3 Chem-Unit)

Principle

It is possible to differentiate between strong and weak electrolytes by measuring their electrical conductance. Strong electrolytes follow Kohlrausch's law, whereas weak electrolytes are described by Ostwald's dilution law. The examination of the concentration dependence of the conductivity allows the molar conductivities of infinitely diluted electrolytes to be determined, and facilitates the calculation of degree of dissociation and the dissociation constants of weak electrolytes.

Tasks

1. Determine the concentration dependence of the electrical conductivity of potassium chloride and acetic acid solutions.
2. Calculate the molar conductivity using data from the measurements taken and determine the molar conductivity at infinite dilution by extrapolation.
3. Determine the dissociation constant of acetic acid.

What you can learn about

• Kohlrausch's law
• Equivalent conductivity
• Temperature-dependence of conductivity
• Ostwald's dilution law

Literature for this article als follows

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