1. ELECTROLYSIS IN IDUSTRY EXTRACTION OF METALS PURIFICATION OF METALS
ELECTROCHEMISTRY
ELECTROLYSIS
MOLTEN COMPOUNDS
AQUEOUS SOLUTION
ELECTROLYSIS IN IDUSTRY
EXTRACTION OF METALS
PURIFICATION OF METALS
ELECTROPLATING OF METALS
VOLTAIC CELL
ELECTROCHEMICAL SERIES

2. ELECTROCHEMISTRY

3. ELECTROCHEMISTRY

4. Substance that can conduct electricity in molten/ aqueous solution
Process-a compound is decomposed into its constituents elements when electric current passes through an electrolyte
ELECTROLYSIS
Substance that can conduct electricity in molten/ aqueous solution
Undergo chemical changes
ELECTROLYTE
Conductors in the form of wires, rods, or plates.
It passes electricity through the electrolyte during electrolysis
Inert: do not take part in chemical reactions
e.g: carbon & platinum
Active : take part in chemical reaction
e.g: copper, silver, mercury
Cathode: negative terminal
Anode: positive terminal
ELECTRODE

5. ELECTROLYSIS SETUP -molten compound-

6. Terms in electrolysis Cation Anion Electrode Inert electrode Battery
Positive terminal
Negative terminal
Cathode
Anode
Electrolysis
Molten
Aqueous
Electrolyte
Non-electrolyte
Discharged

7. anion
cation

8. ELECTROLYSIS OF AQUEOUS SOLUTIONS+
Aqueous solution
A compound
water
NaCl solution (aq)
NaCl (s)
Cation
Na⁺ H⁺
Anion
Cl⁻
OH⁻

9. Electrolysis of NaCl solution
Anode:
4OH⁻  O2 + 2H2O + 4e⁻
Cathode:
2H⁺ +2e⁻H2 C A R B O N C A R B O N
Cl⁻
Na⁺
OH⁻ H⁺ e⁻
Na⁺
Cl⁻ H⁺
OH⁻

10. Factors for selective discharge
Positions of ions in electrochemical series
Concentration of the ions in the electrolyte
Types of electrodes used in the electrolysis

11. Electrolytic cell

12. Electrochemical series (ECS)D C H G
The lower the position of an ion in ECS,the higher is the tendency of the ion to be discharged.

13. Mari menghafal… F..............Fasha SO............sandha
K kalau
Na nak
Ca cari
Mg mak
Al ali
Zn ziarah
Fe flat
Sn satu
Pb pada
H Hari
Cu Cuti
Au ahad
F Fasha
SO sandha
NO Nok
K Kahwin
B Budak
I India
OH OH!

14. Example: Example 1: 0.5 mol dm3 of potassium chloride, KCl solution
Cations : K+ and H+
Anions : Cl-and OH-
Cathode (negative electrode): H+ move to the cathode (ions are selectively discharge)
Anode (positive electrode): OH- move to the anode (ions are selectively discharge)

15. Example 2:
0.1 mol dm3 of copper(II) sulphate, CuSO4 solution
Positive ions (cations): copper ions (Cu2+) and hydrogen ions (H+)
Negative ions (anions): sulphate ions (SO42-) and hydroxide ions (OH-)
Cathode (negative electrode): Cu2+ move to the cathode (ions are selectively discharge)
Anode (positive electrode): OH- move to the anode (ions are selectively discharge)

16. Concentration of Ions in electrolyte
Ion that have high concentration in electrolyte will be discharged.

17. Electrolysis 2.0 mol dm-3 of lead(II) bromide, PbCl2 solution
Cathode:
2H⁺ +2e⁻H₂
Anode:
2Cl⁻ Cl2+ 2e⁻ C A R B O N C A R B O N
if 2 ions are placed very far apart in the ECS, the concentration aspect become insignificant.
Cl⁻
Pb2⁺
OH⁻ H⁺
Pb2
Cl⁻ H⁺
OH⁻

18. Inert electrodes: Carbon and platinum (Both of these electrodes do not react with the electrolytes or products of electrolysis)
Active electrodes: Silver, copper and nickel (Active anode ionizes and concentration of cations in the electrolyte does not change)

19. Electrolysis of CuSO4 Cathode: Anode: Cu2⁺ +2e⁻Cu CuCu2⁺ + 2e⁻ c o p
OH⁻ H⁺
Cu2⁺
SO42⁻ H⁺
OH⁻