jodometriában

Jodometria is a quantitative analytical method used in chemistry to determine the amount of a specific substance in a sample. It is a type of redox titration that involves the use of iodine. The principle behind jodometria relies on the reversible reaction between iodine and iodide ions, forming triiodide ions: I2 + I- <=> I3-. The reaction of interest is then balanced against this iodine-iodide equilibrium.

There are two main approaches to jodometria: direct iodometry and indirect iodometry. In direct iodometry, the substance to be analyzed directly reacts with iodine. For example, reducing agents like thiosulfate can be titrated directly with a standard solution of iodine. The endpoint of the titration is usually detected using starch indicator, which forms a distinct blue complex with iodine.

Indirect iodometry is employed when the substance to be analyzed does not react directly or conveniently with iodine. In this method, an oxidizing agent is added to the sample, which then liberates a stoichiometric amount of iodine. This liberated iodine is subsequently titrated with a standard solution of a reducing agent, typically sodium thiosulfate. Common oxidizing agents used in indirect iodometry include copper(II) ions, which oxidize iodide to iodine, and hypochlorites. Jodometria is widely applied in various fields, including the determination of active chlorine in bleaching agents, the concentration of vitamins like Vitamin C, and the analysis of certain metals. Its accuracy and relative simplicity make it a valuable tool in both laboratory and industrial settings.