[Lifeunderwater]

The equation for an overall reaction is:       I-  +   OCl-    →    IO-   +    Cl-
 
Step 1:    OCl-   +    H2O    →     HOCl   +    OH-     ( fast )
Step 2:    I-    +  HOCl     →     IOH    +    Cl-       ( slow )
Step 3:     IOH    +    OH-    →IO -  +    H2O   ( fast )
          a) Which species in the mechanism above acts as a catalyst?
          b) Which three species in the mechanism above are intermediates?

[cliverlong]

1. Catalysts speed up reactions but appear unchanged in the overall reation. What does not appear in the overall equation, is used in the fast step but recreated in a later step?

2. Intermediates are those species that appear in the steps but do not appear in the overall equation.

3. Why do you think this reaction requires a catalyst?