For the reaction between nitrogen monoxide and chlorine to produce nitrosyl chloride,2NO(g)+ Cl₂(g)→ 2NOCl(g),it is found that tripling the initial concentration of both reactants increases the initial rate by a factor of 27.If only the initial concentration of chlorine is tripled,the initial rate increases by a factor of 3.What is the order of the reaction with respect to Cl₂?

Question

Quizplus · Accepted Answer

Since tripling the initial concentration of both reactants increases the initial rate by a factor of 27, the overall reaction order is the sum of the individual orders with respect to NO and Cl2. Let x be the order with respect to NO and y be the order with respect to Cl2. Then:

3x + 3y = 3^3x
y = 2x

When only the initial concentration of Cl2 is tripled, the initial rate increases by a factor of 3. This means that the order with respect to Cl2 is 1.

Substituting y = 2x into the overall rate equation:

rate = k[NO]^x[Cl2]^2x

When only the initial concentration of Cl2 is tripled, the new rate equation is:

new rate = k[NO]^x(3[Cl2])^2x = 3k[NO]^x[Cl2]^2x

Taking the ratio of the two rate equations:

3 = 27^(1/x)

x = 1

Therefore, the order of the reaction with respect to Cl2 is 2x = 2, and the overall reaction order is:

rate = k[NO][Cl2]^2

For the Reaction Between Nitrogen Monoxide and Chlorine to Produce