Electrolysis

Question 1

Define electrolysis.

Answer 1

Electrolysis is the chemical decomposition of a compound brought about by a flow of an electric current through an aqueous solution of the compound or the molten compound.

Question 2

Define an electrode.

Answer 2

An electrode is a solid electrical conductor that carries electric current into the electrolyte. (It is often made of an inert metal such as platinum or graphite.)

Question 3

Define an electrolyte.

Answer 3

An electrolyte is a molten liquid or aqueous solution that contains mobile ions and can conduct electricity.

Question 4

Define an electrolytic cell.

Answer 4

An electrolytic cell refers to the entire setup where a pair of electrodes is immersed in an electrolyte and electrical energy from the battery causes a chemical reaction to take place.

Question 5

Define a cathode.

Answer 5

A cathode is an electrode where reduction takes place.

Question 6

Define an anode.

Answer 6

A anode is an electrode where oxidation takes place.

Question 7

An experiment is conducted to electrolyse molten lead(II) bromide using graphite electrodes.
a) Write half equation, with state symbols, for the reactions taking place at the cathode and at the
anode.
b) Describe the observation at the anode.

Answer 7

a)
Cathode:
Pb ^2+ (l) + 2e ^- -> Pb (l)
Anode:
2Br ^- (l) -> Br2 (g) + 2e ^-

b) Reddish brown fumes are formed.