Question 1
A metal object is to be gold-plated by an electrolytic procedure using aqueous AuCl
3 electrolyte. Calculate the number of moles of gold deposited in 3.0 min by a constant current of 10. A.
◦ 6.2 × 10
–3 mol
◦ 9.3 × 10
–3 mol
◦ 1.8 × 10
–2 mol
◦ 3.5 × 10
–5 mol
◦ 160 mol
Question 2
Aluminum does not corrode as does iron, because
◦ Al does not react with O
2.
◦ A protective layer of Al
2O
3 forms on the metal surface.
◦ Al is harder to oxidize than is Fe.
◦ Fe gives cathodic protection to Al.
◦ The electrical circuit cannot be completed on an Al surface.