Prepare 0.1 mol/l Ceric Sulfate Solution

General Information:

    One liter of this solution contains 33.224 g of ceric sulfate (Ce(SO4)2,
    molecular weight: 332.24).

Procedure:
    Weigh 55 g of ceric ammonium sulfate, transfer into a beaker, mix with 31 ml of sulfuric acid, and add carefully a few 20-ml portions of water to dissolve the mixture. Cover the beaker, allow to stand overnight, filter through a glass filter, and add water to make 1,000 ml.
 

Standardization: 

 Weigh accurately about 0.2 g of arsenic trioxide (standard reagent), previously dried at 100ˆ for 1 hour, add 25 ml of sodium hydroxide solution (2 ˠ 25), and dissolve while shaking. Add 100 ml of water, 10 ml of diluted sulfuric acid (1 ˠ 3), 2 drops of o-phenanthroline TS, and 2 drops of a solution of osmic acid in 0.05 mol/l sulfuric acid (1 ˠ 400), and titrate with 0.1
mol/l ceric sulfate until the red color of the solution changes to light blue.

                                                      Weight (g) of arsenic trioxide * 1,000 
   Normality factor =  ___________________________________________
                                            Volume (ml) of 0.1 mol/l ceric sulfate consumed * 4.946