Question

For the following reaction, identify the element that was oxidized, the element that was reduced, and the oxidizing agent. Give an explanation for each answer.

Zn + H2SO4 ZnSO4 + H2

Answer 1

Zn on the left side becomes Zn(2+) on the right side.
To get a positive charge, you lose electrons. Losing electrons = oxidation!
The SO4(2-) ion maintains a -2 charge on both side so is neither oxidized nor reduced.
The H however, has a +1 charge on the left and a 0 charge (diatomic gas) on the right. This decrease in charge results as an addition of a negative charge, or an electron. Adding electrons is defined as reduction.

The species oxidized is known as the reducing agent This is because the oxidized species lets off electrons which can then be an aide in the reducing process. It donates the electrons to it. Conversely, the reduced species is the oxidizing agent because it will accept the electrons that the oxidized species discards.
Because of this relationship, oxidation will never exist without reduction. They come in a pair and are balanced in such a way to make sure that all electrons are accounted for -- in redox chemistry there are no electrons flying around in space! Hope that helps