The rate of decomposition of acetaldehyde, CH_3 CHO(g), into CH_4(g) and CO(g) in the presence of I_2(g) at 800 K follows the rate law rate of reaction = k[CH_3 CHO][I_2] The decomposition is believed to occur by the following two-step mechanism: step 1: CH_3 CHO(g) + I_2(g) rightarrow CH_3 I(g) + Hl(g)+ CO(g) step 2: CH_3 l (g) + HI(g) rightarrow CH_4 (g) + I_2 (g)
Which species is the catalyst for the overall reaction?
Which step in the proposed mechanism is most likely the rate-limiting step?