Question

Given below is the decomposition of hydrogen peroxide in alkaline medium, which is catalysed by iodide ions : 2H₂O₂ → 2H₂O + O₂ (I⁻, alkaline medium). The above reaction takes place in two steps : Step I : H₂O₂ + I⁻ → H₂O + IO⁻ (slow). Step II : H₂O₂ + IO⁻ → H₂O + I⁻ + O₂. Molecularity of Step I and Step II is :

The rate of a chemical reaction is expressed either in terms of decrease in the concentration of reactants or increase in the concentration of a product per unit time. Rate of the reaction depends upon the nature of reactants, concentration of reactants, temperature, presence of catalyst, surface area of the reactants and presence of light. Rate of reaction is directly related to the concentration of reactant. Rate law states that the rate of reaction depends upon the concentration terms on which the rate of reaction actually depends, as observed experimentally. The sum of powers of the concentration of the reactants in the Rate law expression is called order of reaction while the number of reacting species taking part in an elementary reaction which must collide simultaneously in order to bring about a chemical reaction is called molecularity of the reaction. Answer the following questions: