Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Hypochlorite Solution 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 Sodium Hypochlorite Solution 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: Assay and Sodium Hydroxide.
NaOCl
Formula Wt 74.44
CAS No. 7681-52-9
Note: Sodium hypochlorite is available in various dilution strengths ranging from 5% to 10%. The use of this product as a standard allows adjusted dilutions to compensate for assay values not equivalent to 2.5%. Always standardize the sodium hypochlorite solution just before use. This solution and subsequent dilutions are unstable.
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . clear, yellow liquid Applications . . . . . . . . . . . . . . . . . . . . . . . . chlorine standard
SPECIFICATIONS Assay (available Cl) . . . . . . . . . . . . . . . . . . . ≥5.0% Cl Maximum Allowable Sodium hydroxide (NaOH) . . . . . . . . . . . . . . . 2.5%
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4351 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By indirect iodometric titration of available chlorine). Weigh accurately about 3 mL of sample in a glass-stoppered iodine flask, and dilute to about 50 mL with water. Add 2 g of potassium iodide and 10 mL of glacial acetic acid. Stopper immediately, and allow to stand in the dark for 10 min. Add 150 mL of water, and titrate the liberated iodine with 0.1 N sodium thiosulfate, adding 3 mL of starch indicator near the end point. One milliliter of 0.1 N sodium thiosulfate corresponds to 0.00355 g of available chlorine.
Sodium Hydroxide Place 50 mL of 12% barium chloride reagent solution and 30 mL of 3% hydrogen peroxide reagent solution in a 250 mL beaker. Using a pH meter, neutralize to pH 7.5 with 0.1 N sodium hydroxide. Add 10 g of sample, accurately weighed with the use of a Smith weighing burette, stir vigorously for 1 min, and again titrate to pH 7.5 with 0.1 N hydrochloric acid. Calculate the NaOH content using the following equation:
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4351 ACS Reagent Chemicals, Part 4
