Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Potassium Antimony Tartrate Trihydrate (Antimony Potassium Tartrate Trihydrate) 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 Potassium Antimony Tartrate Trihydrate 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: Assay, Titrable Acid or Base, Loss on Drying, and Arsenic.
K2(C4H2O6Sb)2 • 3H2O
Formula Wt 667.87
CAS No. 11071-15-1
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . transparent, white solid Applications . . . . . . . . . . . . . . . . . . . . . . . . catalyst in phosphate analysis Aqueous solubility . . . . . . . . . . . . . . . . . . . . slightly soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.0–103.0% K2(C4H2O6Sb)2 · 3H2O Maximum Allowable Titrable acid or base . . . . . . . . . . . . . . . . . . 0.020 meq/g Loss on drying . . . . . . . . . . . . . . . . . . . . . . 2.7% Arsenic (As) . . . . . . . . . . . . . . . . . . . . . . . . 0.015%
TESTS Assay (By iodometric titration of antimony). Weigh accurately about 0.5 g of sample, transfer to a 250 mL beaker, and dissolve in 50 mL of water. Add 5.0 g of potassium sodium tartrate tetrahydrate, 2 g of sodium borate decahydrate, and 3 mL of starch
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4275 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
indicator solution. Titrate immediately with 0.1 N iodine volumetric solution to the production of a persistent blue color. One milliliter of 0.1 N iodine corresponds to 0.01670 g of K2(C4H2O6Sb)2 · 3H2O.
Titrable Acid or Base Dissolve 1.0 g in 50 mL of carbon dioxide-free water, and titrate to a pH of 4.5 using 0.01 N hydrochloric acid or 0.01 N sodium hydroxide as required. Not more than 2.0 mL of either titrant should be required.
Loss on Drying Weigh accurately 1.0 g, and dry in a tared, preconditioned dish at 105 °C to constant weight.
Arsenic Dissolve 0.1 g in 5 mL of hydrochloric acid, and add 10 mL of a freshly prepared solution of 20 g of stannous chloride dihydrate in 30 mL of hydrochloric acid. Mix, transfer to a color-comparison tube, and allow to stand for 30 min. Viewed downward over a white surface, the color of the solution is not darker than that of a standard containing 0.015 g of arsenic in 100 mL of solution.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4275 ACS Reagent Chemicals, Part 4
