Question

Show that the molecularity of a complex reaction cannot be determined by the stoichiometry of the reaction.

Answer 1

The reactions that occur in two or more steps are called complex reactions. The stoichiometry of complicated reactions balanced equations cannot determine their molecularity. This is due to the possibility that their balanced equations contain a significant number of reactant molecules.

\[\ce{2NO + 2H2 -> N2 + 2H2O}\]

\[\ce{2FeCl3 + 6KI -> 2FeI2 + 6KCl + I2}\]

\[\ce{2KMnO4 + 16HCl -> 2KCl + 2MnCl2 + 5Cl2 + 8H2O}\]

For these reactions to occur in a single step, a significant number of reactants (based on their stoichiometry) must collide simultaneously.