Question

The above reaction is an example of: \[F{e_2}{O_3} + 2Al \to A{l_2}{O_3} + 2Fe\].
A.Combination
B.Decomposition
C.Displacement Reaction
D.Double decomposition reaction

Answer 1

Hint: To answer this question, you should chemical reaction and its types. A chemical reaction is in which the bonds are broken within reactant molecules, and new bonds are formed within product molecules to form a new substance.

Complete step by step answer:
1. Combination reaction: A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product).
Example: \[CaO + C{O_2} \to CaC{O_3}\]​, in this reaction calcium oxide is combined with carbon dioxide to form calcium carbonate.
2. Decomposition reaction: A Decomposition reaction is a reaction in which a single component breaks down into multiple products. Certain changes in energy in the environment have to be made like heat, light or electricity breaking bonds of the compound.
Consider the example of the decomposition of calcium carbonate \[CaC{O_{3}} \to CaO + C{O_2},\] in this reaction calcium carbonate is decomposed to calcium oxide and carbon dioxide.
3. Displacement reaction: A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule.
\[Fe\left( s \right) + CuS{O_4}\left( {aq.} \right) \to FeS{O_{4}}\left( {aq} \right) + Cu\left( s \right),\] in this reaction, Fe displaces copper to form ferric sulphate.
In the chemical reaction \[F{e_2}{O_3} + 2Al \to A{l_2}{O_3} + 2Fe\].
The above reaction is known as displacement reaction iron oxide reacts with aluminium to form aluminium oxide and iron metal.

Hence, the correct option is C.

Note:
A substance is said to undergo a physical change when only the physical properties of the reactant change while chemical change refers to a substance combined with another to form a new substance. Atoms or ions or molecules which react to form a new substance are called reactants; the new atoms or molecules formed are products. Chemical changes are irreversible except by further chemical reactions.