Answer :
Balanced chemical reaction : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.
Double-displacement reaction : It is defined as the reaction in which the cation of two reactants molecule exchange their places to give two different products.
(a) The balanced chemical reaction will be:

(b) The balanced chemical reaction will be:

(c) The balanced chemical reaction will be:

(d) The balanced chemical reaction will be:
