Question

For the elementary reaction NO₃ + CO → NO₂ + CO₂, the molecularity of the reaction is ______, and the rate law is rate=.

Answer 1

The molecularity for the reaction NO₃ + CO → NO₂ + CO₂ is bimolecular. At 100 °C, the rate law for NO₂ + CO → NO + CO₂ is second order in NO₂ and zero order in CO, thus rate = k[NO₂]². Above 225 °C, the rate law becomes first order in both reactants.

Step-by-step explanation:

The molecularity of the elementary reaction NO₃ + CO → NO₂ + CO₂ is bimolecular, meaning that two reactant molecules are involved in the step. However, the given information relates to a different reaction, NO₂ + CO → NO + CO₂, at 100 °C, which is second order in NO₂ and zero order in CO. This tells us that the rate law for the reaction at this temperature would be rate = k[NO₂]². Notably, for temperatures above 225 °C, the rate law for the reaction changes to being first order in both NO₂ and CO, meaning the rate law would then be rate = k[NO₂][CO], indicative of a bimolecular reaction consistent with a single-step mechanism.