Naphthol Green B - ACS Reagent Chemicals (ACS Publications)

This monograph for Naphthol Green B provides, in addition to common physical constants, a general description including typical appearance and applica...
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Monograph pubs.acs.org/doi/book/10.1021/acsreagents

Naphthol Green B (Acid Green 1) 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 Naphthol Green B provides, in addition to common physical constants, a general description including typical appearance and applications. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Clarity of Solution and Suitability as a Mixed Indicator for Complexometry.

C30H15FeN3Na3O15S3

Formula Wt 878.46

CAS No. 19381-50-1

GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . dark green to black solid Applications . . . . . . . . . . . . . . . . . . . . . . . . indicator

SPECIFICATIONS Clarity of solution . . . . . . . . . . . . . . . . . . . . Passes test Suitability as a mixed indicator for complexometry Passes test

© 2017 American Chemical Society

A

DOI:10.1021/acsreagents.4235 ACS Reagent Chemicals, Part 4

ACS Reagent Chemicals

Monograph

pubs.acs.org/doi/book/10.1021/acsreagents

TESTS Clarity of Solution Dissolve 0.02 g in 100 mL of water that contains 0.5 mL of ammonium hydroxide. Not more than a trace of turbidity or insoluble matter should remain.

Suitability as a Mixed Indicator for Complexometry Using the test sample, prepare metalphthalein-screened indicator solution. Mix 50 mL of water and 50 mL of ethyl alcohol. Add 10.0 mL of 0.1 M EDTA volumetric solution, 10 mL of ammonium hydroxide, and 0.3 mL of the metalphthalein-screened indicator solution. Titrate with 0.1 M barium nitrate reagent solution. The color change is from gray-green to magenta. Add 0.05 mL of 0.1 M EDTA. The color should return to a gray-green.

© 2017 American Chemical Society

B

DOI:10.1021/acsreagents.4235 ACS Reagent Chemicals, Part 4