The gas-phase isomerization of methyl isocyanide (CH3NC) to acetonitrile (CH3CN) has been studied with and without an acid catalyst. The following rate constants were measured at two temperatures.
k (uncatalyzed): k1=1.2×10−4s−1 at 350 K; k2=4.9×10−3s−1 at 400 K
k (catalyzed): k1∗=6.8×10−3s−1 at 350 K; k2∗=1.9×10−1s−1 at 400 K
(a) Determine the activation energy for the uncatalyzed pathway using the two rate constants provided.
(b) Determine the activation energy for the catalyzed pathway using the corresponding rate constants.
(c) Using the activation energies obtained in parts (a) and (b), predict the ratio k∗/k at 425 K. State any assumption you must make and comment on the validity of that assumption.