Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Calcium Chloride Desiccant 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 Calcium Chloride Desiccant 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 and Titrable Base.
CaCl2
Formula Wt 110.98
CAS No. 10043-52-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
hygroscopic solid desiccant melting point, 772 °C freely soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥96.0% CaCl2 Maximum Allowable Titrable base . . . . . . . . . . . . . . . . . . . . . . . 0.006 meq/g
TESTS Assay (By complexometric titration of calcium). Weigh accurately about 2.5 g in a 250 mL beaker. Dissolve in 100 mL of water, and add 5 mL of 10% hydrochloric acid. Transfer to a 250 mL volumetric flask, dilute to the mark with water, and mix. Pipette 50.0 mL of the sample solution to a 400 mL beaker, add 75 mL of water, and add while stirring 20 mL of 0.1 M EDTA from a 50 mL burette. Adjust the pH using a pH meter to above 12 with 10% sodium hydroxide reagent solution. Add 300 mg of
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4079 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
hydroxynaphthol blue indicator mixture and continue the titration immediately with 0.1 M EDTA volumetric solution to a blue color. One milliliter of 0.1 M EDTA corresponds to 0.0111 g of CaCl2.
Titrable Base Dissolve 5.0 g in 50 mL of water, and add 0.10 mL of phenolphthalein indicator solution. If any pink color is produced, it should be discharged by not more than 3.0 mL of 0.01 N hydrochloric acid.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4079 ACS Reagent Chemicals, Part 4
