Barium Hydroxide and Ammonium Thiocyanate (Endothermic)

概要

This highly endothermic acid-base reaction absorbs so much heat that it can freeze water beneath the flask. Mixing barium hydroxide octahydrate with ammonium thiocyanate drops the temperature below -20 C. The ammonium ion acts as a weak acid donating protons to hydroxide.

参加者

日常の例

This is one of the most dramatic endothermic reaction demonstrations, where a wet board freezes to a beaker as the reaction proceeds.

産業上の重要性

この反応は主に吸熱過程とエントロピー駆動反応の教育的デモンストレーションとして使用され、熱力学の概念ΔG = ΔH - TΔSを示しています。