Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Chlorate 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 Sodium Chlorate 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, Bromate, Chloride, Sulfate, Heavy Metals, Iron, Calcium, Magnesium, and Potassium.
NaClO3
Formula Wt 106.44
CAS No. 7775-09-9
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless or white solid oxidimetric reagent melting point, 248 °C soluble in 1 mL cold, 0.5 mL hot
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% NaClO3 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Bromate (BrO3) . . . . . . . . . . . . . . . . . . . . . . 0.015% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 5 ppm Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.002% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.002% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.01%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4339 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By argentimetric titration of chloride after reduction). Weigh accurately about 0.5 g of sample, transfer to a glassstoppered conical flask, and dissolve in 100 mL of water. Add 25 mL of fresh 6% sulfurous acid and 5 mL of 25% nitric acid, and heat for 30 min to remove the excess sulfur dioxide. Cool, add 50.0 mL of 0.1 N silver nitrate volumetric solution and 10 mL of toluene, and shake vigorously. Titrate the excess silver nitrate with 0.1 N ammonium thiocyanate volumetric solution, using ferric ammonium sulfate indicator solution. One milliliter of 0.1 N silver nitrate corresponds to 0.01064 g of NaClO3.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 250 mL of water.
Bromate [Part 2: Direct Electrometric Methods; Specific Polarographic Procedures; Polarographic Procedure for Bromate and Iodate]. Use 1.0 g of sample and 0.5 g of calcium chloride dihydrate in 25 mL of solution. For the standard, add 0.15 mg of bromate ion (BrO3). Also prepare a reagent blank.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 0.2 g. Use only nitric acid that is free from lower oxides of nitrogen in the test.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Use 5.0 g.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve 2.5 g in 20 mL of dilute hydrochloric acid (1:1). Evaporate the solution to dryness on a hot plate (~100 °C), add 5 mL more of dilute hydrochloric acid (1:1), and again evaporate to dryness. Dissolve the residue in about 20 mL of water, and dilute with water to 25 mL. For the standard–control solution, add 0.02 mg of lead ion (Pb) to 0.5 g of sample, and treat exactly as the 2.5 g sample.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Dissolve 2.0 g in 20 mL of dilute hydrochloric acid (1:1), and evaporate to dryness on a hot plate (~100 °C). Add 5 mL of dilute hydrochloric acid (1:1), and again evaporate to dryness. Dissolve the residue in 50 mL of dilute hydrochloric acid (1:25), and use the solution without further acidification. In preparing the standard, use the residue from evaporation of 15 mL of hydrochloric acid.
Calcium, Magnesium, and Potassium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4339 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Calcium, Magnesium, and Potassium
S a m p l e S t o c k S o l u t i o n . Dissolve 5.0 g in 25 mL of dilute hydrochloric acid (1:3), and digest in a covered beaker on a hot plate (~100 °C) until the reaction ceases. Uncover the beaker, and evaporate to dryness. Add 10 mL of dilute hydrochloric acid (1:3), and again evaporate to dryness. Dissolve in dilute hydrochloric acid (1:99), and dilute to 100 mL with dilute hydrochloric acid (1:99) (1 mL = 0.05 g).
For the Determination of Calcium, Magnesium, and Potassium
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
0.20
0.004; 0.008
A/A
Yes
K
766.5
0.20
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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DOI:10.1021/acsreagents.4339 ACS Reagent Chemicals, Part 4
