AP Chemistryeasymcq1 pt
What is the molecularity of the elementary step 2NO + O2 -> 2NO2?
A.Termolecular
B.Unimolecular
C.Bimolecular
D.Zero-molecular
Explanation
Core Concept
Molecularity counts the reactant particles that collide in a single elementary event. Three molecules take part here: two NO molecules plus one O2 molecule. The step is therefore termolecular, and being elementary its rate law would be rate = k[NO]^2[O2]. Termolecular events like this are uncommon because a simultaneous three-body collision is statistically unlikely.
Correct Answer
ATermolecular
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