Experimental rate data was collected for the following reaction. Determine the rate law.
2 NO + Cl_{2} ® 2 NOCl

















The rate law will have the form Rate = k [NO]^{x} [Cl_{2}]^{y}.
we have an equation with three unknowns (k, x, and y); Rate is measured. We need at least three different measurements of Rate to be able to solve this problem.
1 1.2 ×10^{–4} = k × 0.010^{x} × 0.010^{y} 2 2.3 ×10^{–4} = k × 0.010^{x} × 0.020^{y} 3 9.6 ×10^{–4} = k × 0.020^{x} × 0.020^{y}
Now, we can solve for the three unknowns,
divide equations 2/1
Divide equations 3/2
We now know both x and y. We can solve for k using any one of the three equations.