electrolysis of aqueous solutions Flashcards
1
Q
what does aqueous mean
A
dissolved in water
2
Q
what do water molecules ionise(split) into
A
hydrogen ions(H+) and hydroxide ions(OH-)
3
Q
when is hydrogen produced at the cathode
A
if the metal is more reactive than hydrogen
4
Q
why is platinum often used as an electrode
A
very unreactive
5
Q
what is the half equation for the cathode
A
Cu2+ + 2e- – Cu (reduction)
6
Q
what is the half equation for the anode
A
4OH- – O2 + 2H2O + 4e- (oxidation)
7
Q
what happen if the aqueous solution contains halide ions
A
the halogen will be produced at the anode
8
Q
what is a halide ion
A
negatively charged ions that are made up of a halogen atom and an extra electron.
9
Q
half equations for aqueous sodium chloride
A
cathode = 2H+ + 2e- – H2
anode = 2Cl- – Cl2 + 2e-
