Electrolysis
Energy Conversion
Electrical ener 2 chemical ener
i.e. Have electric current & get chem reaction.
Also known as electrolytic cell.
Non-spontaneous chem reaction forced 2 occur by potential difference set up by
power source (e.g. Battery).
▪ Non-spontaneous if RA forced 2 reduce while OA forced 2 oxidise.
Electrodes made
from unreactive
substances (platinum,
Pt / graphite, C) &
placed in same ionic
solution / molten
Negative ions ionic compound.
(anions) migrate 2
anode w/h =
oxidised.
Positive ions (cations)
migrate 2 cathode
w/h = reduced.
Two Types Of Cells
1. Molten Ionic Solid eg. NaCl 2. Ionic Solution eg. NaCl solution
Solid melted 2 allow ions 2 move Solid dissolved in water 2 allow ions
towards opposite electrodes. move freely in solutions.
NB! water can act as reactant &
must check.
When working w/ ionic solution water = 1 of reactants.
Water can reduce acc 2:
2H2O + 2e- → 2OH- + H2 Eo = -0,83V
If H2O has higher reduction potential than +ion = water reduce and not ion.
Water can oxidise acc 2:
2H2O → O2 + 4H+ + 4e- E0 = +1,23V
If H2O has lower reduction potential than –ion = water will oxidise and not ion.
Energy Conversion
Electrical ener 2 chemical ener
i.e. Have electric current & get chem reaction.
Also known as electrolytic cell.
Non-spontaneous chem reaction forced 2 occur by potential difference set up by
power source (e.g. Battery).
▪ Non-spontaneous if RA forced 2 reduce while OA forced 2 oxidise.
Electrodes made
from unreactive
substances (platinum,
Pt / graphite, C) &
placed in same ionic
solution / molten
Negative ions ionic compound.
(anions) migrate 2
anode w/h =
oxidised.
Positive ions (cations)
migrate 2 cathode
w/h = reduced.
Two Types Of Cells
1. Molten Ionic Solid eg. NaCl 2. Ionic Solution eg. NaCl solution
Solid melted 2 allow ions 2 move Solid dissolved in water 2 allow ions
towards opposite electrodes. move freely in solutions.
NB! water can act as reactant &
must check.
When working w/ ionic solution water = 1 of reactants.
Water can reduce acc 2:
2H2O + 2e- → 2OH- + H2 Eo = -0,83V
If H2O has higher reduction potential than +ion = water reduce and not ion.
Water can oxidise acc 2:
2H2O → O2 + 4H+ + 4e- E0 = +1,23V
If H2O has lower reduction potential than –ion = water will oxidise and not ion.
