Oxidation is loss of electrons or increase in oxidatition number whilst reduction is the gain of electrons or a decrease in oxidation number.
We will find the oxidation state of the chlorine in NaClO:
So chlorine as an oxidation state of +1 in NaClO and -1 in NaCl. There is a decrease in oxidation number so the chlorine is being reduced.
We will determine the oxidation number of S in H2SO4:
Sulfur as an oxidation number of -2 in H2S and +6 in H2SO4. There is an increase in the oxidation number so silfur is being oxidized.