Well none since molecules are a group of two or more atoms electrically bonded with one another. However, there are gases that does not naturally bond due to their stability and can be found in nature as pure elements. But these are not considered as molecules.
(By the way, these gases are the noble gases that can be found on the last column of the periodic table)
Explanation:
Since, the given reaction is as follows.
Hence, rate law of the reaction is as follows.
R = ![k[NO][Cl_{2}]](https://tex.z-dn.net/?f=k%5BNO%5D%5BCl_%7B2%7D%5D)
As it is known that rate of a reaction depends on the initial concentration of products. So here, the rate of reaction will depend on the concentration of NO and
. Since, power of the concentrations of each of these is equal to 1. Therefore, order of the reaction is equal to 1 + 1 = 2.
According to the rate law, reactants involved in the rate determining step are NO and
. Hence, first step of the mechanism is the rate determining step.
Also, according to the rate of reaction doubling the concentration of NO will double the rate of reaction.
The number of reactants taking part in a single step of the reaction is known as molecularity of the reaction. Therefore, molecularity of the first step of the reaction is 2.
Both the given steps are not termolecular.