Experimental studies show that the reaction 2H2(g)+Cl2(g)→2HCl(g) obeys the rate law
rate=k[H2][Cl2]1/2
Which of the following proposed mechanisms is (are) consistent with this rate law?
Mechanism I
Step 1: Cl2(g)⇌2Cl(g) (fast)
Step 2: H2(g)+Cl(g)→H2Cl(g) (slow)
Step 3: H2Cl(g)+Cl(g)→2HCl(g) (fast)
Mechanism II
Step 1: H2(g)+Cl2(g)→2HCl(g) (slow, elementary)
a) Mechanism II only
b) Both Mechanisms I and II
c) Mechanism I only
d) Neither Mechanism I nor II