begin mathsize 36px style A subscript 1 B subscript 1 space end subscript plus space A subscript 2 B subscript 2 space end subscript space rightwards arrow space A subscript 1 B subscript 2 space end subscript plus space A subscript 2 B subscript 1 space end subscript space end style

A1B1 , A2B2  = Reactants ; A1B, A2B= Products