Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Potassium Ferrocyanide Trihydrate (Potassium Hexacyanoferrate(II) Trihydrate) Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents
ABSTRACT This monograph for Potassium Ferrocyanide Trihydrate provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Insoluble Matter, Chloride, and Sulfate.
K4Fe(CN)6•3H2O
Formula Wt 422.39
CAS No. 14459-95-1
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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pale yellow solid moderately strong oxidizer when coupled with ferricyanide dehydrates partially from 60 °C and completely at 100 °C 28 g in 100 mL at 12 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.5–102.0% K4Fe(CN)6 · 3H2O Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . Passes test
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4288 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By titration of reducing power). Weigh accurately about 1.6 g and dissolve in 250 mL of water. Add 30 mL of 25% sulfuric acid reagent solution, and titrate with 0.1 N potassium permanganate volumetric solution to a change from yellow to orange-yellow. One milliliter of 0.1 N potassium permanganate corresponds to 0.04224 g of K4Fe(CN)6 · 3H2O.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 200 mL of water.
Chloride Dissolve 2.0 g in 175 mL of water, filter if necessary through a chloride-free filter, add 2.5 g of cupric sulfate crystals dissolved in 25 mL of water, mix thoroughly, and allow the precipitate to settle in a cylinder. To 10 mL of the clear supernatant liquid, add 1 mL of nitric acid, 10 mL of water, and 1 mL of silver nitrate reagent solution. Any turbidity should not exceed that produced by 0.01 mg of chloride ion (Cl) in an equal volume of solution containing the quantities of nitric acid and silver nitrate used in the test and enough cupric sulfate to match the color in the test solution.
Sulfate Dissolve 5.0 g in 100 mL of water without heating, filter promptly, and to 10 mL (0.5 g) of the filtrate, add 0.2 mL of glacial acetic acid and 5 mL of 12% barium chloride reagent solution. Any turbidity should not exceed that produced by a standard containing 0.05 mg of sulfate ion (SO4) in an equal volume of solution containing 0.2 mL of glacial acetic acid and 5 mL of 12% barium chloride reagent solution. Compare 10 min after adding the barium chloride to the sample and standard solutions. (Limit about 0.01%.)
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4288 ACS Reagent Chemicals, Part 4
