Question

Hi, i'm working on the lab report for Iodometric determination of Cu in Brass and i need help with these questions. I greatly appreciate your help.

Info: This experiment has two parts: standardization of the thiosulfate solution, and assay of the copper. In the standardization of the thiosulfate solution, a known amount of iodine is created from KIO3 and excess iodide, then titrated with the thiosulfate. In the copper assay, iodine is formed from the reaction between copper and excess iodide, then titrated with the thiosulfate.

1. what is the analyte in this experiment? what concentration range of the analyte is typical in this type of sample? why? how the analyte reaction with iodide works, reaction equation, and conditions for ideal reaction ?

2. How iodometry works, redox chemistry, method by which iodine is assayed, how is endpoint detected, how is iodometry different from iodimetry.

Answer 1

Iodometry, also known as iodometric titration, is a method of volumetric chemical analysis, a redox titration where the appearance or disappearance of elementary iodineindicates the end point.

The disappearance of deep blue color due to the decomposition of the iodine-starch clathrate marks the end point

When an analyte that is a reducing agent is titrated directly with a standard iodine solution, the method is called "iodimetry".

When an analyte that is an oxidizing agent is added to excess iodide to produce iodine, and the iodine produced is determined by titration with sodium thiosulfate, the method is called "iodometry".