Question

Galvanized nails are iron nails that have been plated with zinc to prevent rusting. The relevant reaction is

Zn2+(aq)+2e−→Zn(s)
For a large batch of nails, a manufacturer needs to plate a total zinc mass of 4.00 kg on the surface to get adequate coverage.
How many coulombs of charge are needed to produce 61.2 mol of solid zinc?
Express your answer to three significant figures and include the appropriate units.
Part D
Identify the anode and cathode when plating an iron nail with zinc.
Zinc is the anode and iron is the cathode.
Iron is the anode and zinc is the cathode.
Zinc acts as both the anode and cathode.
Iron acts as both the anode and cathode.

Answer 1

1.18 × 10⁷ c

Iron is the anode and zinc is the cathode.

Step-by-step explanation:

Let's consider the reduction of Zn²⁺.

Zn²⁺(aq) + 2 e⁻ ⇒ Zn(s)

How many coulombs of charge are needed to produce 61.2 mol of solid zinc?

We can establish the following relations:

• When 2 moles of electrons circulate, 1 mol of Zn is produced.
• 1 mole of electrons have a charge of 96468 c (Faraday's constant).

Then, for 61.2 mol of Zn:

`61.2molZn.(2mole^(-) )/(1molZn) .(96468c)/(1mole^(-)) =1.18 * 10^(7) c`

Identify the anode and cathode when plating an iron nail with zinc.

The anode is where the oxidation takes place and the cathode is where the reduction takes place.

Anode (oxidation): Fe(s) ⇒ Fe²⁺(aq) + 2 e⁻

Cathode (reduction): Zn²⁺(aq) + 2 e⁻ ⇒ Zn(s)