Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Mercuric Nitrate Monohydrate or Dihydrate (Mercury(II) Nitrate Monohydrate or Dihydrate) 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 Nitrate Monohydrate or Dihydrate 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, Residue after Reduction, Chloride, Sulfate, and Iron.
Hg(NO3)2 • H2O (monohy- Formula Wt 342.61 drate) Hg(NO3)2 • 2H2O (dihyFormula Wt 360.63 drate)
CAS No. 7783-34-8 CAS No. 22852-67-1
Note: This reagent is available as either the mono- or dihydrate. The label should identify the degree of hydration.
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
white solid; may become colored on exposure to light preparation of standards melting point, 70 °C decomposes
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98.0% Hg(NO3)2 · H2O or Hg(NO3)2 · 2H2O Maximum Allowable Residue after reduction . . . . . . . . . . . . . . . . 0.01% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4215 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.002% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001%
TESTS Assay (By thiocyanate precipitation titration of HgII). Weigh accurately about 0.6 g of sample, and transfer with 100 mL of water to a 250 mL flask. Add 5 mL of nitric acid and 2 mL of ferric ammonium sulfate indicator solution. Cool to 15 °C, and titrate with 0.1 N ammonium thiocyanate volumetric solution to a permanent reddish brown color. One milliliter of 0.1 N ammonium thiocyanate corresponds to 0.01713 g of Hg(NO3)2 · H2O or 0.01803 g of Hg(NO3)2 · 2H2O.
Residue after Reduction Dissolve 10 g in 15 mL of water, 2 mL of nitric acid, and 10 mL of formic acid (96%). 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. Add 0.10 mL of sulfuric acid to the combined filtrate and washings. Evaporate 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. Retain the residue for the test for iron.
Chloride Dissolve 2.0 g in 50 mL of water and 2 mL of formic acid (96%). Add dropwise 10% sodium hydroxide reagent solution until a small amount of permanent precipitate is formed. Digest under a reflux condenser until the mercury is all reduced to the metal and the supernatant liquid is clear. Cool, filter through a chloride-free filter, wash thoroughly, and dilute the filtrate with water to 100 mL. To 50 mL of the dilution, add 1 mL of nitric acid and 1 mL of silver nitrate reagent solution. Any turbidity should not exceed that produced by 0.02 mg of chloride ion (Cl) in an equal volume of solution containing the quantities of reagents used in the test.
Sulfate Dissolve 5.0 g in 50 mL of water and 5 mL of formic acid. Digest under a reflux condenser until the mercury is all reduced to the metal and the supernatant liquid is clear. Cool, filter, and wash thoroughly. To the combined filtrate and washings, add 20 mg of sodium carbonate, and evaporate to dryness on a hot plate (~100 °C). Dissolve the residue in 10 mL of water and 1 mL of dilute hydrochloric acid (1:19), and filter if necessary. To the filtrate, add 1 mL of 12% barium chloride reagent solution. Any turbidity should not exceed that produced by 0.1 mg of sulfate ion (SO4) in an equal volume of solution containing the quantities of reagents used in the test. Compare 10 min after adding the barium chloride to the sample and standard solutions.
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 3 mL of dilute hydrochloric acid (1:1), cover with a watch glass, and digest on a hot plate (~100 °C) for 20 min. Remove the cover, and evaporate to dryness. Dissolve the residue in 2 mL of
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4215 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
dilute hydrochloric acid (1:1), add about 40 mL of water, filter if necessary, and dilute with water to 100 mL. Use 10 mL of this solution.
© 2017 American Chemical Society
C
DOI:10.1021/acsreagents.4215 ACS Reagent Chemicals, Part 4
