Preparation of 0.1M Ferric Ammonium Sulphate Solution
Dissolve 40.0 gm of ferrous ammonium sulphate in a previously cooled mixture of 40 ml. of sulphuric acid and 200 ml. of water, dilute with sufficient boiled and cooled water to produce 1000 ml. Standardize the solution in the following manner
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Standrazition of 0.1M Ferric Ammonium Sulphate
Measure accurately 25.0 ml. of solution into a flask, add 2 drops of 1,10-phenanthroline solution and titrate with 0.1M ferric ammonium sulphate until the red colour changed to pale blue.
Calculation
Molarity = --------------
V1
Where M2 = molarity of 0.1M ferric ammonium sulphate solution.
V2 = volume of 0.1 M ferric ammonium sulphate consumed in ml
V1 = volume of 0.1 M ferrous ammonium sulphate taken in ml.
1,10-phenanthroline
Dissolve 1.5 gm. Of 1,10-phenanthroline in sufficient water to produce 100 ml.
ACCEPTANCE CRITERIA
1) The accuracy of the solution should be within ± 10% of the theoretical concentration.
2) RSD* of the triplicate results of standardization/ re-standardization should not be more than 0.2%.
Reference: I.P./In-House (IP 2007, Vol. I, Page No. 549)
Frequency: Preparation: 01 Month
Standardization: Initially after preparation
Re- standardization: After 15 days
Storage conditions: Store the solution in a light-resistant container at ambient temperature
Precautions (if any): None specific