Question

What are the applications of displacement reactions?

Answer 1

Chemical reactions happen when substances react with each other to form new products. There are various types of reactions, combination, decomposition, displacement, redox, neutralization. A displacement reaction occurs when there is change of atoms between two reactants in the products.

Complete answer:
Chemical reaction is a process where the reactant undergoes various chemical and physical changes to produce new compounds called products. Displacement reactions are a type of one such chemical reaction. Displacement reactions involve the chemical change when more reactive species replaces the less reactive species, this can be a more reactive metal replacing a less reactive one. The more reactive substance attaches on the place from where the less reactive substance had left. A displacement reaction occurs, $A+BC\to B+AC$.
Some applications of displacement reactions are:
-Thermite welding
A process where aluminum and ferrous oxide reacts to form molten iron, which is used for welding of rail tracks. The reaction has Al replacing Fe from $F{{e}_{2}}{{O}_{3}}$ to produce$A{{l}_{2}}{{O}_{3}}$. The reaction is,
$2Al+F{{e}_{2}}{{O}_{3}}\to A{{l}_{2}}{{O}_{3}}+2Fe$
-Blast furnace
In a blast furnace, the iron is extracted from its ore$F{{e}_{2}}{{O}_{3}}$, which is used in making steel. In the reaction carbon replaces Ferrous to form carbon dioxide. The reaction is,
$3C+2F{{e}_{2}}{{O}_{3}}\to 4Fe+3C{{O}_{2}}$
-Metal extraction
Heating metal mixtures in presence of carbon produces metals. For example a $C{{r}_{2}}{{O}_{3}}$mixture is heated that yields chromium. The reaction is
$3C+2C{{r}_{2}}{{O}_{3}}\to 4Cr+3C{{O}_{2}}$
-Indigestion of acid
When we feel the acidity problem, then it is advised to take sodium hydrogen carbonate, that displaces the hydrogen from acid HCl. The reaction is
$HCl+NaHC{{O}_{3}}\to NaCl+{{H}_{2}}C{{O}_{3}}$
Hence, the applications of displacement reaction can be seen in thermite welding, iron extraction, metal extraction and acid indigestion.

Note:
Displacement reactions are also used to displace metals from their aqueous salt solutions. For example, when iron nails are dipped into copper sulfate solution, then iron displaces copper metal and forms ferrous sulfate. The color of blue copper sulfate changes to blue – green by the formation of ferrous sulfate, the reaction is $Fe+CuS{{O}_{4}}\to FeS{{O}_{4}}+Cu$.