Cerium(IV) sulfate solution 0.1 mol/l (0.1 N) (Catalog No. 109092)

  • Reaction type:
    • Redox titration/cerimetry
  • Kind of titration:
    • Direct titration
  • Volumetric standard:
    • Iron(II) ethylenediammonium sulfate (Catalog No. 102402)
    • Arsenic (III) oxide should not be used as volumetric standard because of the high toxicity and the difficult handling.
    • Atmospheric oxygen soxidizes the alkaline solution of As2O3 very easily.
  • Method of initial introduction:
    • Direct weighing

Indication

a) visual: with ferroin indicator solution (Catalog No. 109161); color change from orange to faint blue,
b) potentiometrical: with platinum single rod measuring chain and automatic titrator.

Analytical procedure

Approx. 700–750 mg of iron (II) ethylenediammonium sulfate (Volumetric Standard), dried for 24 h over silica gel, are exactly weighed into a titration vessel of approx. 150–200 ml, dissolved in 50 ml of sulfuric acid 0.5 ml/l and titrated to the color change with the cerium (IV) sulfate solution 0.1 mol/l to be tested.

Calculation

Merck:/Freestyle/LE-Lab-Essentials/Learning Center/LE-Inorganic Reagents-Titration-Example-4-Calculation-1-480x86-10022014.png

t = titer
m = weight of volumetric standard
f = stoichiometric factor (volumetric equivalent in mg/ml)
Cf = correction factor, calculated from the effective content of the volumetric standard cc. to the certificate divided by 100.