Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Nitrite 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 Nitrite 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, Sulfate, Heavy Metals, Iron, Calcium and Potassium.
NaNO2
Formula Wt 69.00
CAS No. 7632-00-0
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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white or slightly yellow solid reducing agent melting point, 271 °C; decomposes above 320 °C 82 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥97.0% NaNO2
Insoluble matter . . . Chloride (Cl) . . . . . Sulfate (SO4) . . . . . Heavy metals (as Pb) Iron (Fe) . . . . . . . . Calcium (Ca) . . . . . Potassium (K) . . . . .
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© 2017 American Chemical Society
Maximum Allowable 0.01% 0.005% 0.01% 0.001% 0.001% 0.01% 0.005%
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DOI:10.1021/acsreagents.4357 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS †
For the Assay and Determination of Chloride, Sulfate, Heavy Metals, and Iron
S a m p l e S o l u t i o n A . Weigh accurately about 10.0 g, dissolve in water, and dilute with water to 100 mL in a volumetric flask (1 mL = 0.1 g).
Assay† (By indirect titration of reductive capacity). Dilute a 10.0 mL aliquot of sample solution A to 100 mL in a volumetric flask. Add 5 mL of sulfuric acid to 300 mL of water, and while the solution is still warm, add 0.1 N potassium permanganate volumetric solution until a faint pink color that persists for 2 min is produced. Then add 40.0 mL of 0.1 N potassium permanganate, and mix gently. Add, slowly and with constant agitation, 10.0 mL of the diluted sample solution, holding the tip of the pipette well below the surface of the liquid. Add 15.0 mL of 0.1 N ferrous ammonium sulfate volumetric solution, allow the solution to stand for 5 min, and titrate the excess of ferrous ammonium sulfate with 0.1 N potassium permanganate volumetric solution. Each milliliter of 0.1 N potassium permanganate consumed by the sodium nitrite corresponds to 0.003450 g of NaNO2.
where V = mL of potassium permanganate required to titrate the excess of ferrous ammonium sulfate.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 10 g dissolved in 100 mL of water.
Chloride† [Part 2: Colorimetry and Turbidimetry; Chloride]. To 2.0 mL of sample solution A (0.2 g sample), add 10 mL of water, slowly add 1 mL of glacial acetic acid, and boil gently for 5 min.
Sulfate† [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 2]. Use 5.0 mL of sample solution A plus 1 mL of hydrochloric acid.
Heavy Metals† [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. To 30 mL of sample solution A (3 g sample), add 5 mL of hydrochloric acid, and evaporate to dryness on a steam bath. Add 5 mL of hydrochloric acid, and again evaporate to dryness. Dissolve in about 20 mL of water, and dilute with water to 25 mL. For the control, add 0.02 mg of lead ion (Pb) to 10 mL of sample solution A (1 g sample), add 5 mL of hydrochloric acid, and treat exactly as the 30 mL of sample solution A.
Iron† [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. To 10 mL of sample solution A (1 g sample), add 5 mL of hydrochloric acid, and evaporate on a hot plate (~100 °C) to dryness. Dissolve the
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4357 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
residue in 2 mL of hydrochloric acid plus about 20 mL of water, filter if necessary, and dilute with water to 50 mL. Use the solution without further acidification.
Calcium and Potassium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium and Potassium
S a m p l e S t o c k S o l u t i o n . Dissolve 10.0 g of sample with water in a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.10 g).
For the Determination of Calcium and Potassium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.50
0.05; 0.10
N/A
No
K
766.5
0.50
0.025; 0.05
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.4357 ACS Reagent Chemicals, Part 4
