The rate of a reaction is expressed in different ways as follows : 1 d[C] 1 d[D] 1 d[A] d[B]. 2 dt 3 dt 4 dt dt The reaction is

Product is Reactant is being formed being consumed 1 1 1 2 3 4 d C d D d A d B dt dt dt dt If 1 2 d C dt is remaining, the stoichiometric coefficient is 2 so to make it per mole, it is divided by