Potassium permanganate solution 0.02 mol/l (0.1 N) (Catalog No. 109122)

• Reaction type:
  • Redox titration/manganometry
• Kind of titration:
  • Direct titration
• Volumetric standard:
  • Sodium oxalate (Catalog No. 102407)
• Method of initial introduction:
  • Division into aliquots by gravimetry

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Indication

a) visual: without indicator using the intrinsic color; first visible pink coloration,
b) potentiometrical: with platinum single-rod measuring chain and automatic titrator.

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Analytical procedure

a) Preparation of a sodium oxalate solution 0.05 mol/l (Volumetric Standard solution)
Approx. 6.70 g of sodium oxalate (Volumetric Standard), dried at 110 °C to constant weight, are exactly weighed and transferred to a weighed 1-l volumetric flask, dissolved in water GR for analysis and made up to 1 l. The total weight is determined to two decimals.

Calculation of the mass fraction w (sodium oxalate) in mg/g solution:



Cf = correction factor, calculated from the effective content of the volumetric standard acc. to the certificate divided by 100.

a) Titration: Approx. 19 g of sodium oxalate solution (Volumetric Standard) are weighed exactly into a beaker or titration vessel of 300 ml, using the difference weighing of a plastic syringe. To this solution 10 ml of sulfuric acid 96 % (attention: heating!)and approx. 170 ml of water GR for analysis, warmed to 80–85 °C, are added and the solution is titrated at this temperature with the potassium permanganate solution 0.02 mol/l to be tested under permanent stirring until the color change. The pink coloration appearing immediately must disappear after the addition of a few ml of the titrant. The decolorized solution is titrated carefully and slowly until again a noticeable faint pink coloration appears.

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Calculation

t = titer
w (sodium oxalate) = mass of sodium oxalate in 1 g of volu metric standard solution
f = stoichiometric factor (volumetric equivalent in mg/ml).

Standard solution which can be checked with the standardized potassium permanganate solution:
Oxalic acid solution 0.05 mol/l.