Question

(ii) Account for the following:
(I) We cannot determine the order of a reaction by taking into consideration the balanced chemical equation.
(II) A bimolecular reaction may become kinetically first order under a specified condition.

Hint:

The reaction order must be determined experimentally, as it depends on the mechanism and concentration dependencies, not just the balanced equation.

Answer 1

(I) The stoichiometry presented in a balanced chemical equation does not directly reveal the reaction order. Experimental observation of how the reaction rate changes relative to reactant concentrations is necessary to determine this.
(II) Under specific circumstances, a bimolecular reaction can exhibit first-order kinetics. This often occurs when one reactant is present in a significant excess, rendering its concentration essentially constant. Consequently, the reaction rate may appear to be first order with respect to the other reactant.