In this question we have to find 3 types of reactions, the reduction half-reaction, which is the reaction that represents which element was reduced (gained electrons), the oxidation half-reaction, which element was oxidized (lost electrons), and the overall redox reaction, where we will put both half-reactions together:
First, let's balance the equation:
Zn + 2 H+ -> Zn2+ + H2
If we split the reduction and oxidation in two reactions:
Reduction:
2 H+ (+2e^-) -> H2, this will be the reduction half-reaction, where 2 hydrogens with lack of electrons will receive 2 electrons and become stable
Oxidation:
Zn (-2e^-) -> Zn^2+, this will be the oxidation half-reaction, where Zn lost 2 electrons and became a cation
Overall:
Zn + 2 H+ -> Zn2+ + H2