Precipitation titration (with Cobra3 Chem-Unit)

Principle

Precipitation reactions which occur stoichiometrically and rapidly, and whose equilibrium lies on the side of the poorly soluble products can also be used titrimetrically. Consequently, a solution which contains both chloride and iodide ions can be titrated with a silver nitrate solution. The course of the titration is monitored potentiometrically and the equivalence points are determined from the inflection points of the potential curve.

Tasks

1. Titrate a solution which contains 10 ml each of 0.1 molar potassium chloride and potassium iodide solutions with a 0.1 molar silver nitrate soltution.
2. Plot the potential of a silver electode measured against a silver / silver chloride reference electrode as a function of the added volumes of standard solution.
3. Determine the equivalence points from the inflection points of the potential curve.

What you can learn about

• Electrode potential
• Cell voltage
• Electrodes of the 1^st and 2^nd type
• Nernst equation
• Argentometry
• Solubility product

Literature for this article als follows

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