Barium Hydroxide and Ammonium Thiocyanate (Endothermic)

Tổng quan

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.

Người tham gia

Ví dụ thực tế

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

Tầm quan trọng công nghiệp

This reaction is primarily used as a teaching demonstration of endothermic processes and entropy-driven reactions, illustrating the thermodynamics concept that ΔG = ΔH - TΔS.