Experiment 21.4 Reactions of Chromium and its Compounds Chromium dissolves in When sodium peroxide When aqueous sodium dilute hydrochloric acid to Na, O,. solution is added hydroxide is added to a give hydrogen and a blue to a green solution of green solution of CrCl3,a solution of CrCl,, which is CrCl3, it is oxidized to a grey-green precipitate of rapidly oxidized by oxygen yellow solution of CrO2 CroH is formed in the air to a green solution of CrCl
Experiment 21.5 Thermal Decomposition of Ammonium Dichromate The Volcano Experiment A pile of orange It then burns The pile becomes red hot. (NH小2CrO2热分解m spontaneously, producing giving the appearance df a a shower of sparks. in volcano in eruption. The flame very exothermic reaction product is dark green Cr, O, which is a hght, (火山实验) fy powder with a considerably greater volume than the original
(NH4 )2CrO4热分解 （火山实验）