Question

Consider the following reaction mechanism.

NO2 + F2 mc020-1.jpg NO2F + F (slow)
NO2 + F mc020-2.jpg NO2F (fast)
Overall: 2NO2 + F2 mc020-3.jpg 2NO2F

Which is the correct rate law for this reaction?
k[NO2][F2]
k[NO2F][F2]
k[2NO2][F]
k[NO2][F]

Answer 1

The rate law for this reaction is:

r = k[NO2][F2].

Hope this helps!

Answer 2

Answer: The correct answer is
`k[NO_2][F_2]`

Step-by-step explanation:

Rate law states that the rate of a reaction is directly proportional to the concentration of the reactants each raised to power a stoichiometric coefficient which is determined experimentally and is called as order.

`Rate=k[A]^x[B]^y`

where,

k = Rate constant

x = Order with respect to A

y = Order with respect to B

In a mechanism, it is determined from the slow step of the reaction.

The slow step of the mechanism is:

`NO_2+F_2\rightarrow NO_2F+F`

The rate of this reaction is given by the expression:

`rate=k[NO_2][F_2]`

Thus, the correct answer is
`k[NO_2][F_2]`