Assign oxidation numbers for the following chemical equation:

Question

2Al + 3H2SO4 ---> Al2(SO4)3 +3 H2

What was oxidized?
What was reduced?

My answer:
Oxidation numbers going from the left side of the chemical eq to the right side..
Al: 0
H: +1
S: +6
O : -2

Al: +3
S: +6
O: -2
H: 1

The Al was oxidized.
I don't know what is reduced because the oxidation numbers seem to be the same for S.. Where is my error??

Answer 1

you err on the right side. H is zero (free element). H was reduced, it gained electrons.