Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Iodic Acid (Iodic(V) Acid) 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 Iodic Acid 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, Residue after Ignition, Chloride, Bromide, Iodide, Nitrogen Compounds, Sulfate, Heavy Metals, and Iron.
HIO3
Formula Wt 175.91
CAS No. 7782-68-5
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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white solid; darkens on exposure to light titration standard melting point, 110 °C; with decomposition soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.5% HIO3 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.01% Residue after ignition. . . . . . . . . . . . . . . . . . 0.02% Chloride and bromide (as Cl) . . . . . . . . . . . . . 0.02% Iodide (I). . . . . . . . . . . . . . . . . . . . . . . . . . Passes test Nitrogen compounds (as N) . . . . . . . . . . . . . . 0.1% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.015% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4174 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By indirect iodometric titration of iodate). Weigh accurately about 0.5 g, transfer to a 250 mL volumetric flask, dissolve in water, dilute with water to volume, and mix thoroughly. Place a 50.0 mL aliquot of this solution in a glass-stoppered conical flask, and add 2 g of potassium iodide and 5 mL of 15% hydrochloric acid. Stopper, swirl, allow to stand in the dark for 10 min, and add 100 mL of cold water. 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. Correct for a blank. One milliliter of 0.1 N sodium thiosulfate corresponds to 0.002932 g of HIO3.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 10 g dissolved in 100 mL of water.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Ignite 5.0 g.
Chloride and Bromide Dissolve 1.0 g in 100 mL of water in a distilling flask. Add 1 mL of 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, filter if necessary through a chloride-free filter, and dilute with water to 100 mL. Dilute 5.0 mL of this solution with 18 mL of water, and add 1 mL of nitric acid 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.
Iodide Dissolve 1.0 g in 20 mL of water. Add 1 mL of chloroform and 0.5 mL of 1 N sulfuric acid volumetric solution, and mix. No violet color should appear in the chloroform within 1 min.
Nitrogen Compounds Dissolve 0.50 g in water, and dilute with water to 200 mL. Transfer 40 mL to a flask connected through a spray trap to a condenser, the end of which dips beneath the surface of 10 mL of 0.1 N hydrochloric acid. Add to the flask 10 mL of 10% sodium hydroxide reagent solution and 0.5 g of aluminum wire in small pieces, allow to stand for 1 h, and slowly distill about 35 mL. To the distillate, add 1 mL of 10% sodium hydroxide reagent solution, dilute with water to 50 mL, and add 2 mL of Nessler reagent. Any color should not exceed that produced when a quantity of an ammonium salt containing 0.1 mg of nitrogen ion (N) is treated exactly like the sample. †
For the Determination of Sulfate, Heavy Metals, and Iron
S a m p l e S o l u t i o n A . Dissolve 10 g in 20 mL of water, and add about 10 mg of sodium carbonate. Add 20 mL of hydrochloric acid, and evaporate to dryness on a hot plate (~100 °C). Repeat the evaporation twice using 10 mL of hydrochloric acid.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4174 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
B l a n k S o l u t i o n B . Evaporate to dryness the quantities of hydrochloric acid and sodium carbonate used to prepare sample solution A. Dissolve the residues in separate 20 mL portions of water, filter if necessary, and dilute each with water to 100 mL (1 mL of sample solution A = 0.1 g).
Sulfate† [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Use 3.3 mL of sample solution A (0.33 g sample).
Heavy Metals† [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dilute 20 mL of sample solution A (2 g sample) to 25 mL. Use 20 mL of blank solution B to prepare the control solution.
Iron† [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Use 5.0 mL of sample solution A (0.5 g sample).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4174 ACS Reagent Chemicals, Part 4
