Barium Hydroxide and Ammonium Thiocyanate (Endothermic)

概述

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.

参与者

日常示例

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

工业重要性

该反应主要用作吸热过程和熵驱动反应的教学演示,阐明热力学概念ΔG = ΔH - TΔS。