Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Cobaltinitrite (Trisodium Hexakis(nitrito-N)cobaltate(3–); Sodium Hexanitritocobaltate(III)) 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 Cobaltinitrite provides, in addition to common physical constants, a general description including typical appearance, applications, and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Insoluble Matter and Suitability for Determination of Potassium.
Na3Co(NO2)6
Formula Wt 403.93
CAS No. 13600-98-1
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . orange-yellow solid Applications . . . . . . . . . . . . . . . . . . . . . . . . detection of potassium Aqueous solubility . . . . . . . . . . . . . . . . . . . . very soluble
SPECIFICATIONS Insoluble matter . . . . . . . . . . . . . . . . . . . . . ≤0.02% Suitability for determination of potassium . . . . Passes test
TESTS Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 5.0 g dissolved in 25 mL of dilute acetic acid (1:25), and allow to stand in a covered beaker for at least 8 h.
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4342 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Suitability for Determination of Potassium Dissolve 1.583 g of potassium chloride in water, and dilute with water to 500 mL. To 10.0 mL of this solution (20 mg of K2O) in a 50 mL beaker, add 2 mL of 1 N nitric acid and 8 mL of water. Dissolve 5 g of the sodium cobaltinitrite in water, dilute with water to 25 mL, and filter. Cool both solutions to approximately 20 °C, and add 10 mL of the sodium cobaltinitrite solution to the potassium chloride solution. Allow to stand for 2 h, and filter through a sintered-glass crucible that has been washed with ethyl alcohol, dried at 105 °C, and weighed. Wash the precipitate with cobaltinitrite wash solution (described below), finally wash with 5–10 mL of ethyl alcohol, and dry at 105 °C. The weight of the potassium sodium cobaltinitrite precipitate [K2NaCo(NO2)6 · H2O] should be between 0.0945 and 0.0985 g.
For the Determination of Suitability for Determination of Potassium
C o b a l t i n i t r i t e Wa s h S o l u t i o n . (0.01 N nitric acid saturated with potassium sodium cobaltinitrite). Transfer 75–100 mg of potassium sodium cobaltinitrite to a 125 mL glass-stoppered flask. Add 50 mL of 0.01 N nitric acid, shake on a mechanical shaker for 1 h, and filter through a fine-porosity sintered-glass funnel. The filtrate is cobaltinitrite wash solution.
Note: If no potassium sodium cobaltinitrite is available, a sufficient amount may be prepared by following the suitability for determination of potassium test, but substituting 0.01 N nitric acid in place of the cobaltinitrite wash solution. When it is possible to follow the suitability procedure as written, the analytical precipitate of potassium sodium cobaltinitrite so obtained may be used to prepare the wash solution.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4342 ACS Reagent Chemicals, Part 4
