Oxidize./Reduce?

Question

In Mg + 2H2SO4 yields MgSO4 + SO2 + H2O....

How would I tell what would be reduced?

Mg is oxidized, right? and what is reduced?

Answer 1

The Mg goes from 0 to +2 in fact in the elemental state the atoms are assigned an oxidation number of zero.In compounds,of the group II elements ( Be, Mg , Ca...) have an oxidation number +2

S goes from +6 to +4. In compounds oxygen is generally assigned the oxidation number -2. For neutral species the sum of oxidation numbers times the number of each kind of atoms adds up zero.Si in SO2 we have 2 O ( o.n. 2(-2) = -4) and S must have o.n. +4