A double replacment is a way of forming a new homogenous mixture. Generally double-replacement reactions involve the exchange of positive ions between two reacting compounds. Typically the compounds...
The phrase 'double replacement reaction' means a chemical reaction between two compounds where the positive ion of one compound is exchanged with the positive ion of another compound
An example would be... (The reaction is made up)
NaSOU4+PoBNF2=>PoBOU4+NaSNF2 The NaS and the PoB switched places.
reactant+compound+Reactant+compund=Product Compound+Product Compound