Answer:
A) Mg ₍s₎ | Mg²⁺₍aq₎║Ni²⁺₍aq₎ | Ni₍s₎
B) Cu₍s₎ | Cu²⁺₍aq₎║ Ag⁺ | Ag⁰₍s₎
C) Cu₍s₎ | Cu²⁺₍aq₎║ Ag⁺ | Ag⁰₍s₎
D) Pt₍s₎ | CuNO₃₍ aq₎ , Cu(NO₃)₂₍aq₎ ║ Au(NO₃)₃₍aq₎ | Au₍s₎
Explanation:
A) Mg + Ni²⁺ → Mg²⁺ + Ni
Mg⁰→ Mg²⁺ + 2e⁻ oxidation anode
Ni²⁺ + 2e⁻ → Ni⁰ reduction cathode
Mg ₍s₎ | Mg²⁺₍aq₎║Ni²⁺₍aq₎ | Ni₍s₎
anode salt bridge cathode
B) 2 Ag⁺₍aq₎ + Cu₍s₎ → Cu²⁺₍aq₎ + 2 Ag₍s₎
2 Ag⁺ + 2e⁻ → 2 Ag⁰ cathode
Cu → Cu²⁺ + 2e⁻ anode
Cu₍s₎ | Cu²⁺₍aq₎║ Ag⁺ | Ag⁰₍s₎
anode salt bridge cathode
C) Mn ₍s₎ + Sn(NO₃)₂ ₍aq₎ → Mn (NO₃)₂ ₍aq₎ + Au₍s₎
Mn⁰ → Mn²⁺+ 2e⁻ anode
Sn²⁺ + 2e⁻ → Sn⁰₍s₎ cathode
Mn₍s₎ | Mn(NO₃)₂ ₍aq₎ ║ Sn(NO₃)₂ ₍aq₎ | Sn₍s₎
anode salt bridge cathode
D) 3CuNO₃₍ aq₎ + Au(NO₃)₃₍aq₎ → 3Cu(NO₃)₂₍aq₎ + Au₍s₎
3Cu⁺ → 3Cu²⁺ + 3e⁻ anode
Au³⁺ + 3e⁻ → Au⁰ cathode
Pt₍s₎ | CuNO₃₍ aq₎ , Cu(NO₃)₂₍aq₎ ║ Au(NO₃)₃₍aq₎ | Au₍s₎
anode salt bridge cathode
Semi-reactions are noted to determine oxidation and reduction. The oxidation reaction occurs at the anode and the reduction reaction at the cathode. In the case of subsections a, b, c the electrodes may be the solid metal, while in the case d the species are in an accusative medium and require the platinum electrode.
