Question

What type of reactions are represented by the following equations:
$(a){\text{ CaO + C}}{{\text{O}}_2}{\text{ }}\xrightarrow{{}}{\text{ CaC}}{{\text{O}}_3}$
$(b){\text{ 2Na + 2}}{{\text{H}}_2}{\text{O }}\xrightarrow{{}}{\text{ 2NaOH + }}{{\text{H}}_2}$
$(c){\text{ Mg + C}}{{\text{u}}_2}{\text{S}}{{\text{O}}_4}{\text{ }}\xrightarrow{{}}{\text{ MgS}}{{\text{O}}_4}{\text{ + Cu}}$
$(d){\text{ N}}{{\text{H}}_4}{\text{N}}{{\text{O}}_2}{\text{ }}\xrightarrow{{}}{\text{ }}{{\text{N}}_2}{\text{ + 2}}{{\text{H}}_2}{\text{O}}$
$(e){\text{ CuS}}{{\text{O}}_4}{\text{ + 2NaOH }}\xrightarrow{{}}{\text{ Cu}}{\left( {OH} \right)_2}{\text{ + N}}{{\text{a}}_2}{\text{S}}{{\text{O}}_4}$

Answer 1

Hint: Chemical reactions are those in which a substance reacts with another substance to form products. Basically there is a chemical change of the substance in the chemical reactions. They are of different types which may include combination reaction, displacement reaction, decomposition reactions and many others.

Complete answer:
$(a){\text{ CaO + C}}{{\text{O}}_2}{\text{ }}\xrightarrow{{}}{\text{ CaC}}{{\text{O}}_3}$
Here calcium oxide is reacting with carbon dioxide to form a third chemical compound called calcium carbonate. Thus we can say that calcium oxide combines with carbon dioxide to form a single compound, calcium carbonate. Thus we can call this reaction a combination reaction.
$(b){\text{ 2Na + 2}}{{\text{H}}_2}{\text{O }}\xrightarrow{{}}{\text{ 2NaOH + }}{{\text{H}}_2}$
Here the sodium metal displaces the hydrogen atom from the water molecule and forms sodium hydroxide with the evolution of hydrogen gas. Thus we can say that sodium metal displaces the hydrogen from water molecules, so it is a displacement reaction.
$(c){\text{ Mg + C}}{{\text{u}}_2}{\text{S}}{{\text{O}}_4}{\text{ }}\xrightarrow{{}}{\text{ MgS}}{{\text{O}}_4}{\text{ + Cu}}$
Now magnesium atoms are reacting with a solution of copper sulphate and form magnesium sulphate with deposition of copper metal. Here we can say that the magnesium atom displaces the copper atom from its position. We will regard this reaction as a displacement reaction.
$(d){\text{ N}}{{\text{H}}_4}{\text{N}}{{\text{O}}_2}{\text{ }}\xrightarrow{{}}{\text{ }}{{\text{N}}_2}{\text{ + 2}}{{\text{H}}_2}{\text{O}}$
Here ammonium nitrate gets decomposed into nitrogen gas and water molecules. Therefore we can regard this reaction as a decomposition reaction where decomposition of ammonium nitrate takes place.
$(e){\text{ CuS}}{{\text{O}}_4}{\text{ + 2NaOH }}\xrightarrow{{}}{\text{ Cu}}{\left( {OH} \right)_2}{\text{ + N}}{{\text{a}}_2}{\text{S}}{{\text{O}}_4}$
Now, copper sulphate reacts with sodium hydroxide to form copper hydroxide and sodium sulphate. We observe that copper of copper sulphate and sodium of sodium hydroxide replace their position with each other. Hence this is also a type of displacement reaction. Since displacement of two atoms takes place we call it a double displacement reaction.

Note:
For combination reactions, two compounds react to form a single product. In case of decomposition reaction, a single compound decomposes into two or more products. In a displacement reaction, the displacement of metal atoms takes place.