Question

Consider the chemical reaction below. Upper Z n (s) plus 2 upper H superscript plus (a q) right arrow upper Z n superscript 2 plus (a q) upper H subscript 2 (g). Which half reaction correctly represents reduction for this equation

Answer 1

• 2H⁺ + 2e⁻ → H⁰₂(g)

Step-by-step explanation:

The chemical equation considered is:

• Zn(s) + 2H⁺ (aq) → Zn²⁺ (aq) + H₂(g)

That is a redox reaction because one both oxidation and reduction are happening.

The element or species that is being reduced is that whose oxidation number is reduced.

On the left side, hydrogen, H, has oxidation number +1, which is shown by the superscrit + to the right of H: H⁺.

On the right side, hydrogen appears in its elemental form: H₂. Thus, its oxidation number is 0.

That means that the hydrogen ion is being reduced, and the half reaction that represents this is:

• 2H⁺ + 2e⁻ → H⁰₂(g)

Which means that two H⁺(aq) ions gain 2 electrons to produce a molecule of H₂(g). The reduction reactions happen due to the gain of electrons.