The gas phase reaction between NO2 and F2 is first order in [NO2] and first order in [F2l. What would happen to the reaction rate if the concentrations of both reactants were halved with everything else held constant? a. It would decrease by a factor of 2. b. It would increase by a factor of 4. c. It would increase by a factor of 2. d. It would remain unchanged. e. It would decrease by a factor of 4.

e. It would decrease by a factor of 4.

Explanation:

first order in [NO2]

first order in [F2]

The rate is then given as;

Rate = k [NO2][F2]

where k = rate constant = And is constant for a reaction.

Let's insert some dummy values (Any values work, just be consistent);

[NO2] = 2

[F2] = 2

K = 3

Rate = 3*2*2

Rate = 12

What would happen to the reaction rate if the concentrations of both reactants were halved with everything else held constant?

[NO2] = 2 / 2 = 1

[F2] = 2 / 2 = 1

K = 3

Rate = 3*1*1

Rate = 3

Comparing both rates (12 and 3); the correct option is;

e. It would decrease by a factor of 4.