Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Potassium Iodate 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 Iodate 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, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Chloride, Bromide, Iodide, Nitrogen Compounds, Sulfate, Heavy Metals, Iron, and Sodium.
KIO3
Formula Wt 214.00
CAS No. 7758-05-6
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless or white solid oxidizing agent melting point, 560 °C, with partial decomposition 8.1 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.4–100.4% KIO3 pH of a 5% solution at 25.0 °C . . . . . . . . . 5.0–8.0
Insoluble matter . . . . . . . . Chloride and bromide (as Cl) Iodide (I). . . . . . . . . . . . . Nitrogen compounds (as N) . Sulfate (SO4) . . . . . . . . . . Heavy metals (by ICP–OES) .
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© 2017 American Chemical Society
Maximum Allowable 0.005% 0.01% 0.001% 0.005% 0.005% 5 ppm
A
DOI:10.1021/acsreagents.4294 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.005%
TESTS Assay (By iodometric titration of oxidizing power). Weigh accurately about 0.14 g, and dissolve in 50 mL of water in a glassstoppered conical flask. Add 3 g of potassium iodide and 1 mL of sulfuric acid. Stopper, swirl, and allow to stand for 3 min. Titrate the liberated iodine with 0.1 N sodium thiosulfate volumetric solution, adding 3 mL of starch indicator solution near the end of the titration. One milliliter of 0.1 N sodium thiosulfate corresponds to 0.003567 g of KIO3.
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 250 mL of water.
Chloride and Bromide Dissolve 1.0 g in 100 mL of water in a flask, filter if necessary through a chloride-free filter, and add 6 mL of 30% hydrogen peroxide and 1 mL of phosphoric acid. Heat to boiling, and boil gently until all the iodine is expelled and the solution is colorless. Cool, wash down the sides of the flask, and add 0.5 mL of hydrogen peroxide. If an iodine color develops, boil until the solution is colorless and for 10 min longer. If no color develops, boil for 10 min. Dilute with water to 100 mL, take 10 mL, and dilute with water to 23 mL. Prepare a standard containing 0.01 mg of chloride ion (Cl) and 0.6 mL of hydrogen peroxide in 23 mL of water. Add 1 mL of nitric acid and 1 mL of silver nitrate reagent solution to each. Any turbidity in the solution of the sample should not exceed that in the standard.
Iodide Dissolve 11 g in 160 mL of water, and add 1 g of citric acid and 5 mL of chloroform. Prepare a control solution containing 1 g of the sample, 1 g of citric acid, and 0.1 mg of iodide ion (I) in 160 mL of water; add 5 mL of chloroform. Shake vigorously and allow the chloroform to separate. Any pink color in the chloroform layer from the sample should not exceed that in the chloroform layer from the control.
Nitrogen Compounds [Part 2: Colorimetry and Turbidimetry; Nitrogen Compounds: Test for Ammonia, Amines, and Nitrogen Compounds Reduced by Aluminum]. Dilute the distillate of a 1.0 g sample to 50 mL. Use 10 mL of the distillate. For the standard, use 0.01 mg of nitrogen ion (N).
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 2]. Evaporate 1.0 g to dryness with 3 mL of hydrochloric acid. Repeat the evaporation two more times. Allow 30 min for turbidity to form.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4294 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Heavy Metals ([Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma−Optical Emission Spectroscopy (ICP–OES); Calculation of Heavy Metals (by ICP–OES) Results], by ICP–OES). Use 2.0 g sample.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 2 (Hydroxylamine and 1,10-Phenanthroline)]. Use 5.0 mL of the solution reserved from the test for heavy metals.
Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Sodium
S a m p l e S t o c k S o l u t i o n . Dissolve 1.0 g of sample in water, add 5 mL of nitric acid, transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.01 g).
For the Determination of Sodium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Na
589.0
0.20
0.005; 0.01
A/A
No
*A/A is air/acetylene.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4294 ACS Reagent Chemicals, Part 4
