Chemistry - Redox Reactions Question with Solution | TestHub

The ammonium salt used for making an artificial volcano is ammonium dichromate, $({\mathrm{NH}}_4{)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$. When heated, it decomposes exothermically to produce green chromium(III) oxide, nitrogen gas, and water vapor, creating a visually striking "volcano" effect.

The decomposition reaction is:

$$({\mathrm{NH}}_4{)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7(s)\stackrel{\Delta }{\to }{\mathrm{Cr}}_2{\mathrm{O}}_3(s)+{\mathrm{N}}_2(g)+4{\mathrm{H}}_2\mathrm{O}(g)$$