What is the sum of the orders for the various reactants?

• A. Rate constant
• B. Catalyst
• C. Overall order
• D. Equilibrium constant

Answer: (C)

In reaction kinetics, the rate law shows how the rate depends on each reactant’s concentration, with an exponent (the order) for each reactant. The overall order of a reaction is simply the sum of these individual orders. So the phrase “sum of the orders for the various reactants” is exactly the overall order.

For example, if the rate law is rate = k[A]^2[B], the order with respect to A is 2 and with respect to B is 1, giving an overall order of 3 (a third-order reaction).

Rate constant is the k in the rate law and does not represent a sum of orders. A catalyst speeds up the reaction but doesn’t introduce an additional order in the simplest rate-law expression. The equilibrium constant describes the relationship of concentrations at equilibrium, not how the rate depends on concentrations over time.