Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Cadmium Chloride, Crystals 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 Cadmium Chloride, Crystals 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, Nitrite, Sulfate, Ammonium, Calcium, Copper, Lead, Potassium, Sodium, and Zinc, and Iron.
CdCl2·2½H2O
Formula Wt 228.35
CAS No. 7790-78-5
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless solid standard solutions melting point, 34 °C freely soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79.5–81.0% CdCl2
Insoluble matter . . . . . . . . Nitrate and nitrite (as NO3) . Sulfate (SO4) . . . . . . . . . . Ammonium (NH4) . . . . . . . Calcium (Ca) . . . . . . . . . . Copper (Cu) . . . . . . . . . . . Lead (Pb) . . . . . . . . . . . . Potassium (K) . . . . . . . . . .
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© 2017 American Chemical Society
Maximum Allowable 0.005% 0.003% 0.005% 0.005% 0.005% 5 ppm 0.005% 0.02%
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DOI:10.1021/acsreagents.4071 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.05% Zinc (Zn) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 5 ppm
TESTS Assay (By complexometric titration of cadmium). Weigh accurately about 0.8 g of sample, and dissolve in about 200 mL of water. Add 15 mL of a saturated hexamethylenetetramine reagent solution and 50 mg of xylenol orange indicator mixture. Titrate with 0.1 M EDTA volumetric solution to a color change of red-purple to lemon yellow. One milliliter of 0.1 M EDTA corresponds to 0.01833 g of CdCl2.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 150 mL of water. Reserve the filtrate and washings for the test for sulfate.
Nitrate and Nitrite [Part 2: Colorimetry and Turbidimetry; Nitrate; Procedure for Nitrate, Method 1 (Brucine Sulfate)].
For the Determination of Nitrate and Nitrite
S a m p l e S o l u t i o n A . In a 50 mL centrifuge tube, dissolve 0.30 g in 3 mL of water by heating on a hot plate (~100 °C). Add 20 mL of nitrate-free sulfuric acid (2:1), and cool in an ice bath. Centrifuge for 10 min, decant the solution into a 100 mL flask, and dilute with 50 mL of brucine sulfate reagent solution. C o n t r o l S o l u t i o n B . In a 50 mL centrifuge tube, dissolve 0.30 g in 2 mL of water and 1 mL of nitrate ion (NO3) standard solution by heating on a hot plate (~100 °C). Add 20 mL of nitrate-free sulfuric acid (2:1), and cool in an ice bath. Centrifuge for 10 min, decant the solution into a 100 mL flask, and dilute with 50 mL of brucine sulfate reagent solution.
Continue with the procedure, starting with the preparation of blank solution C.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Use 1/20 of sample. Allow 30 min for turbidity to form.
Ammonium Dissolve 1.0 g in 80 mL of water, and add with stirring, 20 mL of freshly boiled 10% sodium hydroxide reagent solution. After allowing the precipitate to settle, dilute 20 mL of the clear supernatant liquid with water to 50 mL, and add 2 mL of Nessler
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4071 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
reagent. Any color should not exceed that produced by 0.01 mg of ammonium ion (NH4) in an equal volume of solution containing 4 mL of the 10% sodium hydroxide reagent solution and 2 mL of the Nessler reagent.
Calcium, Copper, Lead, Potassium, Sodium, and Zinc (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Copper, Lead, Potassium, Sodium, and Zinc
S a m p l e S t o c k S o l u t i o n . Dissolve 10.0 g of sample in a 100 mL volumetric flask, add 5 mL of nitric acid, and dilute to the mark with water (1 mL = 0.10 g).
For the Determination of Calcium, Copper, Lead, Potassium, Sodium, and Zinc
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
2.0
0.05; 0.10
N/A
No
Cu
324.7
2.0
0.01; 0.02
A/A
Yes
Pb
217.0
2.0
0.10; 0.20
A/A
Yes
K
766.5
0.20
0.02; 0.04
A/A
No
Na
589.0
0.04
0.01; 0.02
A/A
No
Zn
213.9
0.04
0.01; 0.02
A/A
Yes
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Use 2.0 g.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4071 ACS Reagent Chemicals, Part 4
