Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Mercuric Acetate (Mercury(II) Acetate) 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 Acetate 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, Nitrate, Residue after Reduction, Chloride, Sulfate, Other Heavy Metals, Iron, and Mercurous Mercury.
(CH3COO)2Hg
Formula Wt 318.68
CAS No. 1600-27-7
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . white solid with a faint odor of acetic acid; turns slightly yellow on exposure to light Applications . . . . . . . . . . . . . . . . . . . . . . . . determination of nitrate in chromium compounds Change in state (approximate) . . . . . . . . . . . . melting point, 179 °C, with decomposition Aqueous solubility . . . . . . . . . . . . . . . . . . . . 40 g in 100 mL at 25 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98.0% (CH3COO)2Hg Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.01% Nitrate (NO3) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Residue after reduction . . . . . . . . . . . . . . . . 0.02% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Other heavy metals (as Pb) . . . . . . . . . . . . . . 0.002% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001% Mercurous mercury (as Hg) . . . . . . . . . . . . . . 0.4%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4211 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By thiocyanate precipitation titration of mercuric ion). Weigh accurately about 0.7 g of sample, and dissolve in 50 mL of dilute nitric acid (1:19). Add 2 mL of ferric ammonium sulfate indicator solution, and titrate with 0.1 N ammonium thiocyanate volumetric solution. One milliliter of 0.1 N ammonium thiocyanate corresponds to 0.01593 g of (CH3COO)2Hg.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 10.0 g dissolved in 100 mL of dilute acetic acid (5:95). Also use dilute acetic acid (1:99) as the wash.
Nitrate
For the Determination of Nitrate
S a m p l e S o l u t i o n A . Dissolve 0.50 g completely in 3.0 mL of water in a dry test tube. Put the tube in an ice bath, and immediately, but slowly, add 7 mL of cold chromotropic acid reagent solution while swirling. Keep the tube in the ice bath an additional 2–3 min, remove, and let stand for 30 min, swirling occasionally. C o n t r o l S o l u t i o n B . Dissolve 0.50 g in 0.5 mL of water plus 2.5 mL of nitrate ion (NO3) standard solution in a dry test tube. Put the tube in an ice bath, and immediately, but slowly, add 7 mL of cold chromotropic acid reagent solution while stirring. Keep the tube in the ice bath an additional 2–3 min, remove, and let stand for 30 min, stirring occasionally. B l a n k S o l u t i o n C . Add 7 mL of cold chromotropic acid reagent solution to 3.0 mL of water in a dry test tube immersed in an ice bath. Remove and let stand for 30 min.
Transfer sample solution A and control solution B to dry 15 mL centrifuge tubes, and centrifuge until the supernatant liquid is clear. Set a spectrophotometer at 405 nm, and using 1 cm cells, adjust the instrument to read zero absorbance with blank solution C in the light path, then determine the absorbance of sample solution A. Adjust the instrument to read zero absorbance with sample solution A in the light path, and determine the absorbance of control solution B. The absorbance of sample solution A versus blank solution C should not exceed that of control solution B versus sample solution A.
†
For the Determination of Residue after Reduction, Chloride, Sulfate, Other Heavy Metals, and Iron
S a m p l e S o l u t i o n D . 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 thoroughly washed filter paper, and wash with a small quantity of water. Dilute the filtrate and washings with water to 100 mL in a volumetric flask (1 mL = 0.1 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4211 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
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Residue after Reduction
Evaporate 50 mL (5 g sample) of sample solution D plus 0.10 mL of sulfuric acid to dryness in a tared, preconditioned dish in a well-ventilated 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.
Chloride† [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 2.0 mL of sample solution D (0.2 g sample).
Sulfate† [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 3]. Use 10 mL of sample solution D (1 g sample).
Other Heavy Metals† [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Add 1.0 mL of 1% sodium carbonate reagent solution to 10 mL of sample solution D (1 g sample), and evaporate to dryness. Dissolve the residue in about 20 mL of water, filter, and dilute with water to 25 mL.
Iron† [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. To 10 mL of sample solution D (1 g sample), add about 10 mg of sodium carbonate, and evaporate to dryness. Dissolve the residue in 2 mL of hydrochloric acid, dilute with water to 50 mL, and use the solution without further acidification.
Mercurous Mercury Dissolve 5.0 g in 100 mL of a 12.5% solution of potassium iodide. Add 5.0 mL of 0.1 N iodine and 2 mL of 1 N hydrochloric acid. Allow to stand, protected from the light, for 1 h with frequent agitation. Titrate the iodine with 0.1 N sodium thiosulfate volumetric solution, adding 3 mL of starch indicator solution near the end point, and correct for a complete blank. Not more than 1.0 mL of 0.1 N iodine should be consumed.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4211 ACS Reagent Chemicals, Part 4
