Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Mercuric Oxide, Yellow (Mercury(II) Oxide, Yellow) 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 Mercuric Oxide, Yellow 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 in Dilute Hydrochloric Acid, Residue after Reduction, Sulfate, Chloride, Nitrogen Compounds, and Iron.
HgO
Formula Wt 216.59
CAS No. 21908-53-2
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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yellow or yellow-orange solid catalyst decomposes into mercury and oxygen at 500 °C practically insoluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% HgO Maximum Allowable Insoluble in dilute hydrochloric acid . . . . . . . . 0.03% Residue after reduction . . . . . . . . . . . . . . . . 0.05% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.025% Nitrogen compounds (as N) . . . . . . . . . . . . . . 0.005% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.003%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4217 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By complexometric titration of HgII). Weigh accurately about 0.8 g of sample. Dissolve in 3.5 mL of nitric acid, dilute to about 100 mL with water, and add 50 mg of xylenol orange indicator mixture. Add hexamethylenetetramine reagent solution until the color changes to purple, followed by 3–4 mL in excess, then titrate with 0.1 M EDTA volumetric solution until the color changes to yellow. One milliliter of 0.1 M EDTA corresponds to 0.02166 g of HgO.
Insoluble in Dilute Hydrochloric Acid Dissolve 3.0 g in 30 mL of dilute hydrochloric acid (1:3), heat to boiling, and digest in a covered beaker on a hot plate (~100 °C) for 1 h. Filter through a tared, preconditioned filtering crucible, wash thoroughly, and dry at 105 °C.
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For the Determination of Residue after Reduction and Sulfate
S a m p l e S o l u t i o n A . Dissolve 10.0 g in 15 mL of water, 2 mL of nitric acid, and 10 mL of 96% formic acid. Digest under total reflux until all the mercury is reduced to metal and the solution is clear. Cool, filter through a well-washed filter paper, and wash with a small quantity of water. Dilute the filtrate and washings with water to 200 mL in a volumetric flask (1 mL = 0.05 g).
Residue after Reduction† Evaporate 60 mL (3 g) of sample solution A plus 0.10 mL of sulfuric acid to dryness in a tared, preconditioned dish in a wellventilated hood. Continue heating until the excess sulfuric acid has been volatilized. Finally, ignite at 800 ± 25 °C for 15 min. Correct for the weight obtained in a complete blank test. Retain the residue for the test for iron.
Sulfate† [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 3]. Use 10 mL of sample solution A (0.5 g sample).
Chloride Dissolve 1.0 g in 50 mL of water and 1 mL of 96% formic acid. Add dropwise 10% sodium hydroxide reagent solution until a small amount of permanent precipitate is formed. Digest under a reflux condenser until all the mercury is reduced to metal and the solution is clear. Cool, filter through a chloride-free filter, and dilute with water to 100 mL. Dilute 4.0 mL of this solution with water to 20 mL, 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 reagents used in the test.
Nitrogen Compounds [Part 2: Colorimetry and Turbidimetry; Nitrogen Compounds: Test for Ammonia, Amines, and Nitrogen Compounds Reduced by Aluminum]. Dissolve 0.2 g in 5 mL of dilute hydrochloric acid (1:1). For the standard, use 0.01 mg of nitrogen ion (N) and 5 mL of the dilute acid.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4217 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)]. To the residue obtained in the test for residue after reduction, add 1 mL of hydrochloric acid, 0.15 mL of nitric acid, and about 10 mg of sodium carbonate, cover, and digest on a hot plate (~100 °C) for 15–20 min. Uncover, and evaporate to dryness. Dissolve the residue in 9 mL of hydrochloric acid, and dilute with water to 90 mL. Use 10 mL of this solution and 1 mL of additional hydrochloric acid.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4217 ACS Reagent Chemicals, Part 4
