Question

$\left(N{H}_4{)}_{2}C{r}_2{O}_7\right(s)\to C{r}_2{O}_3(s)$ + .................. + ................

• A. Nitrogen, steam
• B. Nitrogen, oxygen
• C. Water, nitrogen oxide
• D. None of the above

Answer 1

The correct option is A Nitrogen, steam

Ammonium dichromate, $(N{H}_4{)}_{2}C{r}_2{O}_7$, decomposes when heated to produce chromium(III) oxide $\left[C{r}_2{O}_3\right]$, nitrogen gas, and water vapor: $\left(N{H}_4{)}_{2}C{r}_2{O}_7\right(s)\to C{r}_2{O}_3(s)+N_2(g)+4H_{2}O(g)$ While the ammonium dichromate decomposes, it gives off orange sparks and throws the green chromium(III) oxide crystals into the air, producing an effect that looks like a miniature volcanic eruption. The chromium(III) oxide crystals that are produced are "fluffier" than the original ammonium dichromate crystals, and even though a lot of the mass of the starting materials escapes as vapor, the product looks like a larger amount of material.