Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Barium Chloride 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 Barium Chloride 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, Loss on Drying, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Oxidizing Substances, Calcium, Potassium, Sodium, Strontium, Heavy Metals, and Iron.
BaCl2 · 2H2O
Formula Wt 244.26
CAS No. 10326-27-9
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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white solid sulfate determination melting point of the anhydrous salt, 960 °C 36 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% BaCl2 · 2H2O Loss on drying . . . . . . . . . . . . . . . . . . . . . . 14.0–16.0% pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 5.2–8.2 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Oxidizing substances (as NO3). . . . . . . . . . . . . 0.005% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.05% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.0025% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.005% Strontium (Sr) . . . . . . . . . . . . . . . . . . . . . . 0.1% Heavy metals (by ICP–OES) . . . . . . . . . . . . . . 5 ppm Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ppm
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4046 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By complexometric titration of barium). Weigh accurately 0.8 g of sample, and dissolve in 200 mL of water. Add, while stirring, 2.0 mL of 6 M hydrochloric acid reagent solution, and from a 50 mL burette, add 25.0 mL of 0.1 M EDTA volumetric solution. Add 100 mL of methanol, 25 mL of ammonium hydroxide, and about 80–100 mg of metalphthalein-screened indicator solution. Immediately continue titration until color changes from violet to clear colorless. The color change is gradual. One milliliter of 0.1 M EDTA corresponds to 0.02443 g of BaCl2 · 2H2O.
Loss on Drying Weigh accurately about 1.0 g, and dry in a preconditioned weighing bottle at 150 °C to constant weight. (The theoretical loss for BaCl2 · 2H2O is 14.75%.)
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 200 mL of water. The solution should be clear and colorless.
Oxidizing Substances Place 0.10 g in a dry beaker. Cool the beaker thoroughly in an ice bath, and add 22 mL of sulfuric acid that has been cooled to ice-bath temperature. Allow the mixture to warm to room temperature, and swirl the beaker at intervals to effect slow dissolution with gentle evolution of hydrogen chloride. When dissolution is complete, add 3 mL of diphenylamine reagent solution, and digest on a hot plate (~100 °C) for 90 min. Prepare a standard by evaporating to dryness a solution containing 0.005 mg of nitrate (0.5 mL of the standard nitrate solution) and 0.01 g of sodium carbonate. Treat the residue exactly like the sample. Any color produced in the solution of the sample should not exceed that in the standard.
Calcium, Potassium, Sodium, and Strontium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Potassium, Sodium, and Strontium
S a m p l e S t o c k S o l u t i o n A . Dissolve 10.0 g of sample in sufficient water in a beaker, add 5 mL of nitric acid, and transfer to a 100 mL volumetric flask. Dilute to the mark with water (1 mL = 0.10 g). S a m p l e S t o c k S o l u t i o n B . Pipette 10.0 mL of sample stock solution A into a 100 mL volumetric flask and dilute to the mark with water (1 mL = 0.01 g). Add 2.0 mL of a 2.5% potassium chloride reagent solution to the flask for calcium and strontium.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4046 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Calcium, Potassium, Sodium, and Strontium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.04
0.02; 0.04
N/A
No
K
766.5
1.0
0.02; 0.04
A/A
No
Na
589.0
0.10
0.005; 0.01
A/A
No
Sr
460.7
0.05
0.05; 0.10
N/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
Heavy Metals ([Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma−Optical Emission Spectroscopy (ICP–OES); Calculation of Heavy Metals (by ICP–OES) Results], by ICP–OES). Use 2.0 g sample.
Iron Dissolve 5.0 g in 40 mL of water plus 2 mL of hydrochloric acid. Prepare a standard containing 0.01 mg of iron (Fe) in 40 mL of water plus 2 mL of hydrochloric acid. Add 0.10 mL of 0.1 N potassium permanganate to each, dilute with water to 50 mL, and allow to stand for 5 min. Add 3 mL of ammonium thiocyanate reagent solution to each. Any red color in the solution of the sample should not exceed that in the standard.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4046 ACS Reagent Chemicals, Part 4
