The gas-phase decomposition of X2O2 is proposed to occur by the three elementary steps listed below. Activation energies (Ea) were measured at 298 K.
Step 1 X2O2 → 2 XO Ea = 55 kJ mol⁻¹
Step 2 XO + X2O2 → 3 X + O2 Ea = 75 kJ mol⁻¹
Step 3 2 XO → X2 + O2 Ea = 48 kJ mol⁻¹
Which step is expected to be the rate-determining step at 298 K?
a) Step 1
b) Step 2
c) Step 3
d) No single step limits the rate because the activation energies are similar