Consider the single replacement reaction of zinc metal with hydrochloric acid.

1) Write the chemical equation of this reaction knowing that one mole of H₂ is formed from one mole of Zn.

2) Which atom gains electrons, which one loses electrons?

3) What is the reducing agent?

4) Write the net ionic equation for this reaction.

Question

Consider the single replacement reaction of zinc metal with hydrochloric acid.

1) Write the chemical equation of this reaction knowing that one mole of H₂ is formed from one mole of Zn.

2) Which atom gains electrons, which one loses electrons?

3) What is the reducing agent?

4) Write the net ionic equation for this reaction.

| General Chemistry 2

Accepted Answer

1) Zn (s) + 2 HCl (aq) → ZnCl₂ (aq) + H₂ (g)

2) Oxidation state: Zn = 0; Zn in ZnCl₂ = +2

Oxidation state: Cl in HCl = -1; Cl in ZnCl₂ = -1

Oxidation state: H in HCl = +1; H in H₂ = 0

⇒ Zn loses electrons while H gains electrons

3) The oxidation state of H decreases: H is reduced.

Zn is the reducing agent.

4) Zn (s) + 2 H⁺ (aq) + 2 Cl^- (aq) → Zn²⁺ (aq) + 2 Cl^- (aq) + H₂ (g)

Net ionic equation for this reaction: Zn (s) + 2 H⁺ (aq) → Zn²⁺ (aq) + H₂ (g)

Midterm 1 - Question 2 | General Chemistry 2