Iodine and Sodium Thiosulfate Titration

I2 + 2Na2S2O3 → Na2S4O6 + 2NaI

概述

Iodine oxidizes thiosulfate to tetrathionate while being reduced to iodide. This is the basis of iodometric titration, one of the most important analytical techniques in chemistry. Starch indicator turns blue-black with iodine and becomes colorless at the endpoint when all I₂ is consumed.

参与者

角色 物质 系数 状态
反应物 Iodine I 1 (aq)

日常示例

The vitamin C content of fruit juice can be determined by iodometric titration, where ascorbic acid reduces iodine before the starch endpoint.

工业重要性

碘量法是测定水中溶解氧（维克勒法）、余氯、铜含量和食品中维生素C的标准分析方法，广泛应用于水质检测、食品分析和制药质量控制。

属性

类型
Redox
可逆
否
能量
放热
ΔH
-140.0 kJ/mol

相关反应

Iron(II) to Iron(III) Oxidation by Oxygen Bleaching with Sodium Hypochlorite Copper Reduction of Silver Ion Aqua Regia Dissolving Gold Cerium(IV) Reduction by Iron(II) Chlorine Oxidation of Bromide Copper Oxidation by Nitric Acid Hypochlorite Oxidation of Hydrogen Peroxide Hydrogen Peroxide as Oxidizing Agent (Acidic) Displacement of Hydrogen from Acid by Magnesium

Frequently Asked Questions

What is the equation for Iodine and Sodium Thiosulfate Titration?
The balanced equation is: I₂ + 2Na₂S₂O₃ → Na₂S₄O₆ + 2NaI.
What type of reaction is Iodine and Sodium Thiosulfate Titration?
Iodine and Sodium Thiosulfate Titration is a redox reaction.
Is Iodine and Sodium Thiosulfate Titration exothermic or endothermic?
Iodine and Sodium Thiosulfate Titration is exothermic (releases energy). The enthalpy change (ΔH) is -140.0 kJ/mol.