The decomposition of hydrogen peroxide in aqueous solution is observed to proceed rapidly in the presence of iodide ion. A suggested mechanism is shown.
Step 1 (slow): H2O2(aq) + I⁻(aq) → H2O(l) + IO⁻(aq)
Step 2 (fast): H2O2(aq) + IO⁻(aq) → H2O(l) + O2(g) + I⁻(aq)
Which of the following species acts as a catalyst for the overall reaction?
a) IO−(aq)
b) I−(aq)
c) H2O2(aq)
d) O2(g)