The given reaction is,
In this reaction, the positive and negative ions of both the reactants rearrange resulting in the formation of new compounds. Such a reaction is referred to as the double replacement or the double displacement reaction. These type of reactions usually take place in aqueous medium and one of the products is a precipitate.
Double displacement reactions are of three types, precipitation reaction, neutralization reaction and reaction involving the formation of a gas. The given reaction is a precipitation reaction as one of the products is a solid.