Question

The rate law for the reaction

2NO(g) + Cl2(g) → 2NOCl(g)

is given by R = k[NO][Cl2]

If the following is the mechanism for the reaction, NO(g) + Cl2(g) → NOCl2(g) NOCl2(g) + NO(g) → 2NOCl(g)

which of the following statements accurately describes this reaction? Check all that apply.

-2nd order reaction

-The first step is the slow step.

-Doubling [NO] would quadruple the rate.

-Cutting [Cl2] in half would decrease the rate by a factor of two.

-The molecularity of the first step is 1.

-Both steps are termolecular.

Answer 1

Explanation:

Since, the given reaction is as follows.

              $2NO(g) + Cl_{2}(g) \rightarrow 2NOCl(g)$

Hence, rate law of the reaction is as follows.

               R = $k[NO][Cl_{2}]$

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 $Cl_{2}$. 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 $Cl_{2}$. 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.