Question

Chemical volcano is an example of:
(A) Combination reaction
(B) Decomposition reaction
(C) Displacement reaction
(D) None of the above

Answer 1

Hint: Chemical volcano is a reaction when ammonium dichromate decomposes; it gives off orange sparks and throws the green chromium oxide crystals into the air, producing an effect that looks like a miniature volcanic eruption.

Complete-step- by- step answer:
Reaction Equation for Chemical volcano:
${{(N{{H}_{4}})}_{2}}C{{r}_{2}}{{O}_{7}}\overset{Heat}{\mathop{\to }}\,C{{r}_{2}}{{O}_{3}}+4{{N}_{2}}\uparrow +4{{H}_{2}}O$

A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions involve an energy source such as heat, light, or electricity that breaks the bonds of compounds.
According to the above definition of the decomposition reaction, the reaction equation of the chemical volcano is the best example of a decomposition reaction.

Hence option (B) decomposition reaction, is the correct answer.

Additional Information:
We've seen that ammonium dichromate and chromium oxide are two compounds involved in the reaction of chemical volcano eruption. Lets see the detailed information about ammonium dichromate and chromium oxide.

1. Ammonium dichromate is an inorganic compound with the formula ${{(N{{H}_{4}})}_{2}}C{{r}_{2}}{{O}_{7}}$. In this compound, chromium is in +6 oxidation state, known as hexavalent chromium. It is a salt containing ammonium ions and dichromate ions.
2. Chromium oxide is a well known catalyst for complete oxidation, chromium oxide is a green powder mainly used as dye/colorant in chrome green and institutional green. It can also be used as a catalyst in the oxidation of chlorinated hydrocarbons due to its high removal activity and in glasses, optics, ceramics, inks as well as in paints.

Note: Don’t get confused between decomposition reaction and displacement reaction, a decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. In displacement reactions, a metal and a compound of a different metal are involved. In a displacement reaction: a more reactive metal displaces a less reactive metal from its compounds.