Abstract This paper improved the endothermic reaction of barium hydroxide crystal and ammonium chloride crystal, a small amount of water was added into the reactant, and a beaker was reversed on the small beaker, in this way, the success rate of freezing was high, the freezing rate was fast, and the amount of ice increased. Phenolphthalein was added into the frozen water to form ice, which could not only test the formation of ammonia, but also increased the interest of the experiment.
LI Mao-Jian. The Key to Success of Freezing in Reaction of Barium Hydroxide with Ammonium Chloride[J]. Chinese Journal of Chemical Education, 2021, 42(5): 80-82.