Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Ammonium Chloride 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 Ammonium Chloride 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, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Residue after Ignition, Calcium, Magnesium, Heavy Metals, Iron, Phosphate, and Sulfate.
NH4Cl
Formula Wt 53.49
CAS No. 12125-02-9
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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white solid electrolyte sublimation point, 335 °C 39.5 g in 100 mL at 25 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.5% NH4Cl pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 4.5–5.5 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Residue after ignition. . . . . . . . . . . . . . . . . . 0.01% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 5 ppm Heavy metals (by ICP–OES) . . . . . . . . . . . . . . 5 ppm Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ppm Phosphate (PO4) . . . . . . . . . . . . . . . . . . . . . 2 ppm Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4020 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By argentimetric titration of chloride content). Weigh accurately about 0.25 g, and dissolve in 50 mL of water in a 250 mL glass-stoppered flask. Add 1 mL of dichlorofluorescein indicator solution. While stirring, titrate with 0.1 N silver nitrate volumetric solution. The silver chloride flocculates, and the mixture changes to a pink color. One milliliter of 0.1 N silver nitrate corresponds to 0.005349 g of NH4Cl.
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 20.0 g dissolved in 200 mL of water.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Ignite 10.0 g.
Calcium and Magnesium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium and Magnesium
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 80 mL of water, and warm to room temperature. Transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.10 g).
For the Determination of Calcium and Magnesium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
2.0
0.02; 0.04
N/A
No
Mg
285.2
2.0
0.01; 0.02
A/A
Yes
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
†
For the Determination of Heavy Metals, Iron, Phosphate, and Sulfate
S a m p l e S o l u t i o n A . Dissolve 25.0 g in 75 mL of water, and add about 10 mg of sodium carbonate, 10 mL of hydrogen peroxide, and 50 mL of nitric acid.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4020 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
B l a n k S o l u t i o n B . To 75 mL of water, add about 10 mg of sodium carbonate, 10 mL of hydrogen peroxide, and 50 mL of nitric acid. Digest sample solution A and blank solution B in covered beakers on a hot plate (~100 °C) until reaction ceases, uncover, and evaporate to dryness. Dissolve the two residues in separate 5 mL portions of 1 N acetic acid and 50 mL of water, filter if necessary, and dilute with water to 100 mL (1 mL of sample solution A = 0.25 g).
Heavy Metals† [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dilute 16 mL of sample solution A (4 g sample) with water to 25 mL. Use 16 mL of blank solution B to prepare the standard solution.
Iron† [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Use 20 mL of sample solution A (5 g sample). Prepare the standard with 20 mL of blank solution B.
Phosphate† (Page 80[Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma-Optical Emission Spectroscopy (ICPOES); Preconcentration of Ultratrace-Grade Reagents for Analysis by ICP-OES]. Use 2.0 g. sample.
Sulfate† [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. To 10 mL of sample solution A (2.5 g sample) add 5 mL water.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4020 ACS Reagent Chemicals, Part 4
