Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Ferric Nitrate Nonahydrate (Iron(III) Nitrate Nonahydrate) 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 Ferric Nitrate Nonahydrate 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, Chloride, Sulfate, Calcium, Magnesium, Potassium, and Sodium.
Fe(NO3)3 · 9H2O
Formula Wt 403.99
CAS No. 7782-61-8
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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pale mauve solid determination of phosphate melting point, 47 °C very soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.0–101.0% Fe(NO3)3 · 9H2O Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 5 ppm Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.005% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.05%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4144 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By complexometric titration of iron). Weigh accurately about 1.6 g, and transfer to a 400 mL beaker. Dissolve with 200 mL of water, and add 2 mL of 20% hydrochloric acid. From a 50 mL burette, add 30.0 mL of 0.1 M EDTA volumetric solution. Heat the solution to 40–50 °C, and adjust the pH to 2.5 ± 0.2 with 10% sodium acetate reagent solution. Add 0.25 mL of Variamine Blue B indicator solution, and continue the addition of 0.1 M EDTA until burgundy changes to canary yellow. One milliliter of 0.1 M EDTA corresponds to 0.04040 g of Fe(NO3)3 · 9H2O.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20.0 g dissolved in 200 mL of dilute nitric acid (1:99).
Chloride Dissolve 2.0 g in 20 mL of water, filter if necessary through a chloride-free filter, and add 1 mL of nitric acid plus 1 mL of phosphoric acid and 1 mL of silver nitrate reagent solution. Any turbidity should not exceed that produced by 0.01 mg of chloride ion (Cl) in an equal volume of solution containing the quantities of reagents used in the test.
Sulfate
For the Determination of Sulfate
S a m p l e S o l u t i o n . Dissolve 5.0 g in 70 mL of water, heat to boiling, and pour slowly with constant stirring into 100 mL of dilute ammonium hydroxide (1:6). Filter through a folded filter while still hot, and wash with hot water until the filtrate (sample solution) measures 250 mL. Mix thoroughly (1 mL = 0.02 g).
To 25 mL (0.5 g sample) of sample solution, add 5 mL of hydrochloric acid and 10 mL of nitric acid. For the standard, add 0.05 mg of sulfate ion (SO4) and 1.5 mL of ammonium hydroxide to 25 mL of water, and add 5 mL of hydrochloric acid and 10 mL of nitric acid. Digest each solution in a covered beaker on a hot plate (~100 °C) until reaction ceases, uncover, and evaporate to dryness. Dissolve the residues in 4 mL of water plus 1 mL of dilute hydrochloric acid (1:19), filter if necessary through a small filter, wash with two 2 mL portions of water, and dilute with water to 10 mL. To each solution, add 1 mL of 12% barium chloride reagent solution. Any turbidity in the solution of the sample should not exceed that in the standard. Compare 10 min after adding the barium chloride to the sample and standard solutions.
Calcium, Magnesium, Potassium, and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Magnesium, Potassium, and Sodium
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 75 mL of water, transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.10 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4144 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
S a m p l e S t o c k S o l u t i o n B . Transfer 5.0 mL (0.50 g) of sample stock solution A to a 100 mL volumetric flask, dilute to the mark with water, and mix (1 mL = 0.005 g).
For the Determination of Calcium, Magnesium, Potassium, and Sodium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
1.00
0.05; 0.10
N/A
No
Mg
285.2
0.20
0.005; 0.01
A/A
Yes
K
766.5
1.00
0.025; 0.05
A/A
No
Na
589.0
0.04
0.01; 0.02
A/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4144 ACS Reagent Chemicals, Part 4
