0.005 N Iodine VS

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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Transfer 50 mL of 0.1 N iodine VS to a 1-L volumetric flask and dilute with water to volume. Preserve in amber-colored, glass-stoppered bottles.

1 Standardization

See Volumetric Solutions. 1. Introduction

See Titrimetry (541)

Standardize by one of the following procedures. [NOTE-Other standardization procedures may be used. See Volumetric Solutions. 2. Preparation and Standardization 2.3 Standardization)

1.1 Standardization with visual endpoint

Transfer 100.0 mL of iodine solution to a 250-ml flask, add 1 mi. of 1 N hydrochloric acid, swirl gently to mix, and titrate with 0.05 N sodium thiosulfate VS until the solution has a pale yellow color. Add 2 ml of starch TS, and continue titrating until the solution is colorless.
N = (mL Na2S25O3 x N Na2S25O3)/100

1.2 Standardization with potentiometric endpoint

Transfer 100.0 mL of iodine solution to a 250-ml flask, add 1 mL of 1 N hydrochloric acid. swirl gently to mix, and titrate with 0.05 N sodium thiosulfate VS using a combined platinum electrode.

N = (mL Na2S25O3 x N Na2S25O3)/100

(NOTE-If this volumetric solution is used in a qualitative application such as pH adjustment, dissolution medium, or diluent, its standardization is not required.) (USP 1-May-2022)