1) reacting hydrochloric acid with nickel:
Balanced molecular equation: Ni(s) + 2HCl(aq) → NiCl₂(aq) + H₂(g).
Ionic equation: Ni(s) + 2H⁺(aq) + 2Cl⁻(aq) → Ni²⁺(aq) + 2Cl⁻(aq) + H₂(g).
Net ionic equation: Ni(s) + 2H⁺(aq) → Ni²⁺(aq) + H₂(g).
In this reaction, nickel undergoes oxidation, changing from an oxidation state of 0 to +2, while hydrogen is reduced from +1 to 0 (H₂).
2) reacting sulfuric acid with iron:
Balanced molecular equation: Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂(g).
Ionic equation: Fe(s) + 2H⁺(aq) + SO₄²⁻(aq) → Fe²⁺(aq) + SO₄²⁻(aq) + H₂(g).
Net ionic equation: Fe(s) + 2H⁺(aq) → Fe²⁺(aq) + H₂(g).
In this scenario, iron is oxidized from an oxidation state of 0 to +2, while hydrogen experiences reduction from +1 to 0 (H₂).
3) hydrobromic acid reacting with magnesium:
Balanced molecular equation: Mg(s) + 2HBr(aq) → MgBr₂(aq) + H₂(g).
Ionic equation: Mg(s) + 2H⁺(aq) + 2Br⁻(aq) → Mg²⁺(aq) + 2Br⁻(aq) + H₂(g).
Net ionic equation: Mg(s) + 2H⁺(aq) → Mg²⁺(aq) + H₂(g).
This reaction sees magnesium oxidized from 0 to +2, and hydrogen reduced from +1 to 0 (H₂).
4) acetic acid reacting with zinc:
Balanced molecular equation: Zn(s) + 2CH₃COOH(aq) → (CH₃COO)₂Zn(aq) + H₂(g).
Ionic equation: Zn(s) + 2H⁺(aq) + 2CH₃COO⁻(aq) → Zn²⁺(aq) + 2CH₃COO⁻(aq) + H₂(g).
Net ionic equation: Zn(s) + 2H⁺(aq) → Zn²⁺(aq) + H₂(g).
Here, zinc gets oxidized from 0 to +2 (Zn²⁺), while hydrogen is reduced from +1 to 0 (H₂).
