Question

what is double displacement reaction ??

Answer 1

A salt metathesis reaction sometimes called a double replacement reaction ,double displacement reaction or double decomposition reaction, is a chemical process involving the exchange of bondsbetween two reacting chemical species, which results in the creation of products with similar or identical bonding affiliations.[1] This reaction is represented by the general scheme:

A-B + C-D → A-D + C-B

The bond between the reacting species can either be ionic or covalent. Classically, these reactions result in the precipitation of one product.

In older literature, the term double decomposition is frequently encountered. The term double decomposition is more specifically used when at least one of the substances does not dissolve in the solvent, as the ligand or ion exchange takes place in the solid state of the reactant, for example:

AX(aq) + BY(s) → AY(aq) + BX(s).

Answer 2

such a reaction in which exchange of ions take place...
Example : NaCl+BaSO4 ....... NA2SO4+ bacl2...