Zn and HCl
Zn + 2HCl → ZnCl₂ + H₂
Redox balancer
Type the reactants and products with an arrow, without numbers: MnO4- + Fe2+ -> Mn2+ + Fe3+. Leave out H+, OH- and water; they are added for you. Salts and acids such as KMnO4 or HNO3 are fine.
Zn+2HCl→ZnCl₂+H₂
Ionic Zn+2H⁺→Zn²⁺+H₂
- Oxidising agentH⁺
- Reducing agentZn
- Electrons2
OxidationZn 0 → +2
Zn→Zn²⁺+2e⁻
loses 2 e⁻ReductionH +1 → 0
2H⁺+2e⁻→H₂
gains 2 e⁻- Write the skeleton in ionic form
Zn + H⁺ → Zn²⁺ + H₂
Written as ions: HCl as H⁺ + Cl⁻; ZnCl₂ as Zn²⁺ + 2Cl⁻.
Cl⁻ does not change and is left out. - Split into two half reactions
Oxidation: Zn → Zn²⁺ (Zn 0 → +2)
Reduction: H⁺ → H₂ (H +1 → 0) - Balance atoms other than O and H
Oxidation: Zn → Zn²⁺
Reduction: 2H⁺ → H₂ - Balance the charge with electrons
Oxidation: Zn → Zn²⁺ + 2e⁻
Reduction: 2H⁺ + 2e⁻ → H₂ - The electrons are already equal
Oxidation: Zn → Zn²⁺ + 2e⁻
Reduction: 2H⁺ + 2e⁻ → H₂ - Add the halves and cancel what appears on both sides
Zn + 2H⁺ → Zn²⁺ + H₂ - Check
Each side has 1 Zn, 2 H and a total charge of +2. - Put back the ions that do not change
Zn + 2HCl → ZnCl₂ + H₂
- Write the oxidation numbers and find the change
Zn: 0 in Zn → +2 in Zn²⁺, a rise of 2 for Zn → Zn²⁺ (oxidation)
H: +1 in H⁺ → 0 in H₂, a fall of 2 for 2H⁺ → H₂ (reduction) - Make the total rise equal the total fall (2 each)
Zn + 2H⁺ → Zn²⁺ + H₂ - Check
Zn + 2H⁺ → Zn²⁺ + H₂
Each side has 1 Zn, 2 H and a total charge of +2. - Put back the ions that do not change
Zn + 2HCl → ZnCl₂ + H₂
Step by step
Ion-electron method
- Write the skeleton in ionic form
Zn + H⁺ → Zn²⁺ + H₂
Written as ions: HCl as H⁺ + Cl⁻; ZnCl₂ as Zn²⁺ + 2Cl⁻.
Cl⁻ does not change and is left out. - Split into two half reactions
Oxidation: Zn → Zn²⁺ (Zn 0 → +2)
Reduction: H⁺ → H₂ (H +1 → 0) - Balance atoms other than O and H
Oxidation: Zn → Zn²⁺
Reduction: 2H⁺ → H₂ - Balance the charge with electrons
Oxidation: Zn → Zn²⁺ + 2e⁻
Reduction: 2H⁺ + 2e⁻ → H₂ - The electrons are already equal
Oxidation: Zn → Zn²⁺ + 2e⁻
Reduction: 2H⁺ + 2e⁻ → H₂ - Add the halves and cancel what appears on both sides
Zn + 2H⁺ → Zn²⁺ + H₂ - Check
Each side has 1 Zn, 2 H and a total charge of +2. - Put back the ions that do not change
Zn + 2HCl → ZnCl₂ + H₂
Oxidation number method
- Write the oxidation numbers and find the change
Zn: 0 in Zn → +2 in Zn²⁺, a rise of 2 for Zn → Zn²⁺ (oxidation)
H: +1 in H⁺ → 0 in H₂, a fall of 2 for 2H⁺ → H₂ (reduction) - Make the total rise equal the total fall (2 each)
Zn + 2H⁺ → Zn²⁺ + H₂ - Check
Zn + 2H⁺ → Zn²⁺ + H₂
Each side has 1 Zn, 2 H and a total charge of +2. - Put back the ions that do not change
Zn + 2HCl → ZnCl₂ + H₂
Oxidising and reducing agents
- Zn 0 → +2Zn to Zn²⁺: oxidised
- H +1 → 0H⁺ to H₂: reduced
- H⁺oxidising agent, gains electrons
- Znreducing agent, loses electrons
Zn and HCl: quick answers
What is the balanced equation for zinc and hydrochloric acid?
Zn + 2HCl → ZnCl₂ + H₂. In ionic form: Zn + 2H⁺ → Zn²⁺ + H₂.
Which is the oxidising agent and which is the reducing agent?
Zn goes from 0 to +2 and H goes from +1 to 0. H⁺ is the oxidising agent (it is reduced) and Zn is the reducing agent (it is oxidised).
How many electrons are transferred?
2 electrons pass from Zn to H⁺ in the balanced equation as written.