Ammonium ion (NH4^+) reacts with nitrite ion (NO2^-) to yield nitrogen gas and liquid water. The following initial rates of reaction have been measured for the given reactant concentrations.

Question

Expt. # [NH4^+] [NO2^-] Initial rate (M/hr)
1 0.010 0.020 0.020
2 0.015 0.020 0.030
3 0.030 0.010 0.015
What is the rate law (rate equation) for this reaction?

Answer 1

How much of this can you do on your own. For example, have you determined that (NH4^+) is first order? (It is.)
For order of NO2^-
rate = k(NH4^+)(NO2^-)

rate2 = k(0.015)^1(0.020)^x
rate3 = k(0.030)^1(0.010)^x

Divide rate2 equation by rate3 eqn and solve for x. I obtained x = 2.