Electrolysis Flashcards
(16 cards)
Why do covalent compounds not conduct electricity
Because they do not contain charged particles
When can ionic compounds conduct electricity and why
When molten or in a aqueous solution as the ions are free to move
What does PANIC stand for
Positive
Anode
Negative
Is
Cathode
What is a anion
A negative ion
What is a cation
A positive ion
What is a anode
A positive electrode
What is a cathode
A negative electrode
What is a electrolyte
A liquid that undergoes a electrolysis
Define oxidation
The loss of electrons
Define reduction
Gain of electrons
What is OIL RIG
Oxygen
Is
Loss of electrons
Reduction
Is
Gain of electrons
Define electrolysis
The chemical change caused by passing a electric current through a compound that is molten or in a solution
What is the reactivity series
Potassium
Sodium
Calcium
Magnesium
Aluminium
(Carbon)
Zinc
Iron
Lead
(Hydrogen)
Copper
Silver
Gold
Platinum
What happened in electrolysis of molten compounds such as lead (II) bromide
Reaction at cathode:
Pb2+ + 2e- —> pb
Réaction at anode:
2Br- —> Br2 + 2e-
Overall equation:
PbBr2 —> Pb + Br2
What happens at the cathode in electrolysis of a aqueous solution such as sodium chloride
At the cathode there are two possibilities:
Sodium reduced- Na+ + e- —> Na
Hydrogen reduced- 2H+ + 2e- —> H2
If there is a mixture of ions At the cathode the less reactive element will be the product
Hydrogen is less reactive so when we electrolyte sodium chloride hydrogen is produced
What happens at the anode in electrolysis of a aqueous solution such as sodium chloride
At the anode there are two possibilities:
Chloride is oxidised-2Cl- —> Cl2 + 2e- producing chlorine
Hydroxide is oxidised-
4OH- —> O2+2H20 + 4e- producing oxygen
Either the halide is discharged producing a halogen eg chlorine or hydroxide is discharged producing oxygen (and water)
