Electroplating Pennies

Plating of Nickel onto Copper

Source

• Reference: A Demo A Day: Vol 2, Bilash et al., page 262.

Materials Needed

• Power supply and cords with alligator clips (one end)
• NiCl₂·6H₂O (65 g)
• 0.1 M HCl
• Copper (Cu) foil
• Beaker
• Steel wool

Procedure

1. Prepare Nickel Solution:

• Dissolve 65 g of NiCl₂·6H₂O in 500 mL of 0.1 M HCl.

1. Prepare Copper Electrodes:

• Clean the Cu foil (or penny) with steel wool.
• Attach leads to the Cu electrodes.

1. Electrolysis Setup:

• Immerse the Cu electrodes in the nickel solution.
• Note that there is no reaction without current.

1. Initiate Current:

• Turn on the power supply to about 6 volts.
• Observe the plating process.

Chemical Reactions

Table 1: Oxidation and Reduction of Copper and Nickel

Reaction Type	Equation	Standard Electrode Potential (V)
Oxidation of Copper	Cu(s) → Cu²⁺(aq) + 2e⁻	E°ox = -0.34
Reduction of Nickel	Ni²⁺(aq) + 2e⁻ → Ni(s)	E°red = -0.25
Overall Reaction	Cu(s) + Ni²⁺(aq) → Cu²⁺(aq) + Ni(s)	E°tot = -0.59

Table 2: Reduction of Silver and Copper

Reaction Type	Equation	Standard Electrode Potential (V)
Reduction of Silver	2Ag⁺(aq) + 2e⁻ → 2Ag(s)	E°red = 0.80
Reduction of Copper	Cu²⁺ + 2e⁻ → Cu(s)	E°red = -0.34
Overall Reaction (with Nickel)	Cu(s) + Ni²⁺(aq) → Cu²⁺(aq) + Ni(s)	E°tot = 0.46

Table 3: Reduction of Lead and Zinc

Reaction Type	Equation	Standard Electrode Potential (V)
Reduction of Lead	Pb²⁺(aq) + 2e⁻ → Pb(s)	E°red = -0.13
Reduction of Zinc	Zn(s) → Zn²⁺ + 2e⁻	E°red = 0.76
Overall Reaction (with Nickel)	Cu(s) + Ni²⁺(aq) → Cu²⁺(aq) + Ni(s)	E°tot = 0.63