Q.Identify the order for the following reactions

Step 1 (i). Rusting of iron is a classic zero order process -- the reaction rate at the metal surface is limited and does not depend on how much $O_2$/moisture is available in the surrounding environment, so it proceeds at a constant rate regardless of reactant concentration.

Step 2 (ii). Radioactive disintegration of $_{92}U^{238}$ is, like all radioactive decay processes, first order -- the decay rate at any instant depends only on the amount of undecayed nuclide present, raised to the first power. …

Recall each reaction type's characteristic order from the chapter (rusting = zero order, radioactive decay = always first order), and directly …

• Reading the orders in (iii) from the balanced equation's coefficients (2 and 3) instead of from the EXP …