Consider this mechanism:
step 1: clo-(aq) + h2o(l) hclo(aq) + oh-(aq) (fast)
step 2: i-(aq) + hclo(aq) hio(aq) + cl-(aq) (slow)
step 3: oh-(aq) + hio(aq) h2o(l) + io-(aq) (fast)

what is the overall reaction?
a.
hclo (aq) + h2o (l) oh- (aq) + cl- (aq)
b.
i- (aq) + hclo (aq) hio (aq) + cl- (aq)
c.
oh- (aq) +hio (aq) h2o (l) + io- (aq)
d.
clo- (aq) + i- (aq) cl- (aq) + io- (aq)
e.
clo- (aq) + h2o(l) hclo(aq) + oh- (aq)

Explanation:

Given a reaction mechanism, we will typically have catalysts and intermediates which will not be observed in the final balanced overall reaction. In order to obtain a net reaction, we need to add all the separate steps of the given reaction.

First of all, the reactants are combined followed by a combination of products. The repeating species on both sides of the final equation are then canceled out. Let's sum everything we have in our steps:

Repeating species that can be canceled out are:

This leaves a net reaction of: