What is the molecularity of each of the following elementary reactions? Write the rate law for each. (c) NO(g) + Cl₂(g) → NOCl₂(g)

Key Concepts

Molecularity

Molecularity refers to the number of reactant molecules involved in an elementary reaction. It can be classified as unimolecular (one molecule), bimolecular (two molecules), or termolecular (three molecules). Understanding molecularity is crucial for determining the rate law of a reaction, as it directly influences how the concentration of reactants affects the reaction rate.

Elementary Reaction

An elementary reaction is a single step process in a chemical reaction mechanism where reactants convert directly to products. The rate law for an elementary reaction can be derived directly from its molecularity, as the rate is proportional to the concentration of the reactants raised to the power of their coefficients in the balanced equation. This makes elementary reactions simpler to analyze compared to complex reactions involving multiple steps.

Rate Law

The rate law expresses the relationship between the rate of a chemical reaction and the concentration of its reactants. For an elementary reaction, the rate law can be written using the stoichiometric coefficients of the reactants. In the case of the reaction NO(g) + Cl2(g) → NOCl2(g), the rate law would be rate = k[NO][Cl2], indicating that the reaction is first order with respect to both NO and Cl2.