Iodine and Sodium Thiosulfate Titration

I2 + 2Na2S2O3 → Na2S4O6 + 2NaI

概要

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.

参加者

役割 物質 係数 状態
反応物 Iodine I 1 (aq)

日常の例

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

産業上の重要性

ヨウ素滴定は水質試験（溶存酸素量、ウィンクラー法）、食品の酸化度測定、酸化剤・還元剤の定量に使われる標準分析手法である。

特性

タイプ
Redox
可逆的
いいえ
エネルギー
発熱性
ΔH
-140.0 kJ/mol

関連する反応

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.