How can the overall order of a reaction be determined?

A. Add the exponents in an equilibrium constant expression.
B. Add the coefficients in the balanced equation.
C. Count the number of different reactants.
D. Examine experimental data for the reaction over time.

I believe that the answer is D

The overall order of a reaction can be determined by examining experimental data for the reaction over time. Therefore, the correct answer is D.

The overall order of a reaction can be determined by examining experimental data for the reaction over time. This involves conducting a series of experiments with varying concentrations of reactants and measuring the rate of reaction.

To determine the overall order, the reaction rate is plotted against the concentration of each reactant. If changing the concentration of a reactant has no effect on the rate, then the reactant is not involved in the rate-determining step and its order is zero. If changing the concentration of a reactant has an effect on the rate, the order of that reactant can be determined by observing how the rate changes with variations in concentration.

The overall order is determined by summing up the individual orders of each reactant. For example, if changing the concentration of reactant A has an effect on the rate and the rate is doubled when the concentration of A is doubled, then the order of A is 1. If changing the concentration of reactant B has no effect on the rate, then the order of B is 0.

Therefore, option D is the correct answer - the overall order of a reaction can be determined by examining experimental data for the reaction over time.

http://www.chemguide.co.uk/physical/basicrates/orders.html