hichem belarbi

This chapter provides a comprehensive and rigorously pedagogical introduction to oxidation-reduction (redox) equilibria, bridging fundamental chemical principles with practical analytical applications. It begins by establishing the foundational concept of the oxidation number, providing clear rules for its determination and demonstrating its utility in tracking electron transfer and balancing reactions.

The chapter systematically develops the half-reaction method for balancing redox equations, offering a robust, step-by-step protocol applicable in both acidic and basic media. This methodological rigor is consistently applied to clinically relevant examples, including the oxidation of glucose and the titration of hydrogen peroxide.

A significant portion of the chapter is dedicated to the use of redox titrations in analytical chemistry. It covers key operational concepts such as equivalence point, endpoint, and the criteria for a successful titration. Three detailed, applied case studies are presented:

1. Iron Ore Analysis: A classic permanganometric titration used to calculate iron content, emphasizing stoichiometry, dilution factors, and the critical analysis of error sources.

2. Vitamin C Assay: An iodometric titration to verify label claims, detailing the use of starch as an indicator and introducing the principles of back-titration.

3. Hydrogen Peroxide Assay: A permanganometric titration combined with an iodometric confirmatory method, exploring the importance of titrant standardization and the correction of matrix interferences.

The chapter concludes by discussing the advantages, limitations, and specific error sources of different redox methodologies, equipping students with the critical thinking skills necessary for reliable quantitative analysis in clinical and pharmaceutical settings.

Keywords: Redox Equilibria, Oxidation Number, Half-Reaction Method, Balancing Equations, Redox Titration, Permanganometry, Iodometry, Stoichiometry, Equivalence Point, Titrant Standardization, Analytical Chemistry, Clinical Assays, Pharmaceutical Quality Control.