Consider the chemical reaction below. Zn(s) + 2H+(aq) -> Zn2+(aq) + H2(g). Which half reaction correctly represents reduction for this equation?

2H⁺(aq) + 2e⁻ → H₂(g)

Explanation:

In a redox reaction, one substance is oxidized (Loosing electrons) and the other substance is reduced (Gaining electrons).

In the reaction:

Zn(s) + 2H⁺(aq) → Zn²⁺(aq) + H₂(g)

The Zn is loosing 2 electrons (From oxidation state = 0 to oxidation state = +2). That means is beeing oxidized.

And the hydrogen is gaining one electron each atom (From oxidation state +1 to oxidation state 0). Hydrogen is beeing reduced.The half-reaction that represents its reduction is:

- lead + phosphoric acid = hydrogen + lead(ii) phosphate