CHAPTER 17

Question 1

Consider these three reactions:

a. Fe3+ → Fe
b. Cr → Cr3+
c. MnO42- → MnO4-

These reactions show, respectively:

oxidation, oxidation, reduction.

oxidation, oxidation, oxidation.

reduction, oxidation, oxidation.

oxidation, reduction, oxidation.

Answer 1

reduction, oxidation, oxidation.

Question 2

An active metal electrode was found to lose mass in an oxidation-reduction reaction. From this, we conclude that this electrode is the:

anode and the metal is reduced.

anode and the metal is oxidised.

cathode and the metal is oxidised.

cathode and the metal is reduced.

Answer 2

anode and the metal is oxidised.

Question 3

Consider a battery with the overall reaction:

Cu(s) + 2 Ag+ (aq) → 2 Ag (s) + Cu2+ (aq)

Which one statement below is correct?

cathode: Cu (s) → Cu2+ (aq) + 2e-
anode: Cu (s) → Cu2+ (aq) + 2e-

none of these

anode: 2 Ag+(aq) + 2e- → 2Ag (s)

Answer 3

anode: Cu (s) → Cu2+ (aq) + 2e-

Question 4

If a sample of iron and a sample of zinc come into contact, the zinc corrodes but the iron does not. If a sample of iron comes into contact with a sample of copper, the iron corrodes but the copper does not. The order of strongest to weakest reductant for these elements would be:

Fe, Cu, Zn

Zn, Fe, Cu

Cu, Fe, Zn

Cu, Zn, Fe

Answer 4

Zn, Fe, Cu

Question 5

Which one of the following statements about fuel cells and batteries is correct?

Batteries are self-contained, whereas, fuel cells will continue to work as long as they are constantly supplied with an electron donor and acceptor and the products are expelled.

none of these

Batteries are self-contained, whereas, fuel cells are continually recharged using a battery charger.

Batteries and fuel cells are self-contained, but fuel cells are constantly supplied with electricity and fuel.

Answer 5

Batteries are self-contained, whereas, fuel cells will continue to work as long as they are constantly supplied with an electron donor and acceptor and the products are expelled.