The reaction of NO2(g) and CO(g) is thought to occur in two steps:
Step 1 Slow NO2(g) + NO2(g) → NO(g) + NO3(g)
Step 2 Fast NO3(g) + CO(g) → NO2(g) + CO2(g)
Add the elementary steps to give the overall, stoichiometric reaction.
(Use the lowest possible coefficients. Use the pull-down boxes to specify states such as (aq) or (s). If a box is not needed, leave it blank.)