[candiishop]

Nitric oxide gas (NO) reacts with chlorine gas according to the equation
NO + ½Cl2 ----> NOCl.
The following initial rates of reaction have been measured for the given reagent concentrations.
Expt. #        Rate (M/hr)        NO (M)         Cl2(M)
    1                    1.19               0.50            0.50
    2                    4.79               1.00            0.50
    3                    9.59               1.00            1.0
Which of the following is the rate law (rate equation) for this reaction?
 
a) rate = k[NO]
 
b) rate = k[NO][Cl2]1/2
 
c) rate = k[NO][Cl2]
 
d) rate = k[NO]2[Cl2]
 
e) rate = k[NO]2[Cl2]2

I try working this question many times and none of my answer matches the multiple choice above.

For Cl2 (ie constance NO):
Rate= 4.79/ 1.19= 2^2

:. Rate= k [NO]x [Cl2]2

For NO:
Rate= 9.59/4.79 = 2^1

:. Rate = k[NO] [Cl2]2

[green-goblin]

When the concentration of NO doubles the rate more than tripples so NO is to the second order. When the concentration of [Cl] doubles the rate only doubles so [Cl] is to the first order. So i would go for d.