Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Potassium Hydrogen Sulfate, Fused (Potassium Pyrosulfate)
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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 Hydrogen Sulfate, Fused 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: Acidity, Water, Insoluble Matter, Chloride, Phosphate, Heavy Metals, Iron, Calcium, Magnesium, and Sodium.
CAS No. 7790-62-7
Note: This product is a mixture of potassium pyrosulfate, K2S2O7, and potassium hydrogen sulfate, KHSO4.
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless solid fusion flux for ores and minerals melting point, 325 °C soluble
SPECIFICATIONS Acidity (as H2SO4) . . . . . . . . . . . . . . . . . . . . 37.5–38.6% Maximum Allowable Water (H2O) . . . . . . . . . . . . . . . . . . . . . . . . 2.5% Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.01% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.002% Phosphate (PO4) . . . . . . . . . . . . . . . . . . . . . 0.001% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4292 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.002% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.001% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.01%
TESTS Acidity
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(By acid–base titrimetry). Weigh accurately about 4.0 g, dissolve in 50 mL of water, and titrate with 1 N sodium hydroxide volumetric solution, using methyl orange indicator solution. One milliliter of 1 N sodium hydroxide corresponds to 0.04904 g of H2SO4.
Water Weigh accurately about 5 g, dissolve in water, and dilute with water to 250 mL. Evaporate 25.0 mL of the solution to dryness in a tared, preconditioned platinum vessel, and ignite at 800 °C to remove all sulfuric acid and leave potassium sulfate. Calculate the percentage of potassium sulfate (B). Calculate the percentage of sulfite (A) from the percentage of sulfuric acid obtained in the test for acidity. One percent of sulfuric acid is equivalent to 0.8163% of sulfite. Calculate the percentage of water (C) as the difference between 100% and the sum of the percentages of sulfite and potassium sulfate.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Dissolve 20 g in 200 mL of water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 0.50 g.
Phosphate Dissolve 2.0 g in 15 mL of dilute ammonium hydroxide (1:2), and evaporate to dryness. Dissolve the residue in 25 mL of approximately 0.5 N hydrochloric acid, add 1 mL of ammonium molybdate reagent solution and 1 mL of 4(methylamino)phenol sulfate reagent solution, and allow to stand for 2 h at room temperature. Any blue color should not exceed that produced by 0.02 mg of phosphate ion (PO4) in an equal volume of solution containing the quantities of reagents used in the test, including the residue from evaporation of 5 mL of ammonium hydroxide.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve 4.0 g in about 20 mL of water, and dilute with water to 32 mL. Use 24 mL to prepare the sample solution, and use the remaining 8.0 mL to prepare the control solution.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4292 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Dissolve 5.0 g in 80 mL of dilute hydrochloric acid (1:3), and boil gently for 10 min. Cool, dilute with water to 100 mL, and use 10 mL of the solution.
Calcium, Magnesium, and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Magnesium, and Sodium
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S a m p l e S t o c k S o l u t i o n . Dissolve 5.0 g of sample with water in a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.05 g).
For the Determination of Calcium, Magnesium, and Sodium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
1.0
0.02; 0.04
N/A
No
Mg
285.2
1.0
0.01; 0.02
A/A
Yes
Na
589.0
0.10
0.01; 0.02
A/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4292 ACS Reagent Chemicals, Part 4
