Compounds A and B react according to the following chemical equation.

A(g) + 2B(g)  2C(g)

The concentration of either A or B was changed keeping the concentrations of one of the reactants constant and rates were measured as a function of initial concentration. The following results were obtained. Choose the correct option for the rate equations for this reaction.

Experiment Initial
concentration of
[A]/mol L–1
Initial
concentration of
[B]/moI L–1
Initial
rate (mol L–1 s–1)
1.
2.
3.
0.30
0.30
0.60
0.30
0.60
0.30
0.10
0.40
0.20
1. Rate=kA2B
2. Rate=kAB2
3. Rate=kAB
4. Rate=kA2B0