The molecularity of the following elementary reaction is NH₄NO₂ → N₂ + 2H₂O

Explanation:

The molecularity of an elementary reaction is defined as the number of reactant particles that come together to form the products in a single step.

In the given reaction, NH₄NO₂ is directly decomposing into N₂ and 2H₂O. Therefore, this is an elementary reaction, and its molecularity can be determined by counting the number of molecules or atoms that are involved in the reaction.

As we can see, NH₄NO₂ is the only reactant molecule in this reaction, and it is breaking down into two product molecules, N2 and 2H2O. Therefore, the molecularity of this reaction is one.

The reaction can be represented as:

NH₄NO₂ → N₂ + 2H₂O

where NH₄NO₂ is the reactant and N₂ and H₂O are the products.

This reaction is an example of a unimolecular reaction, where only one molecule of the reactant is involved in the reaction. The decomposition of NH4NO2 is a first-order reaction, where the rate of the reaction is proportional to the concentration of NH₄NO₂.

The reaction can be further explained by looking at the balanced chemical equation:

NH₄NO₂ → N₂ + 2H₂O

1 molecule of NH₄NO₂ → 1 molecule of N₂ + 2 molecules of H₂O

In conclusion, the molecularity of the given elementary reaction NH₄NO₂ → N₂ + 2H₂O is one, which means it is a unimolecular reaction where one molecule of the reactant is involved in the reaction.

Only one reacting species is involved, therefore it is a unimolecular reaction.