1. ELECTROLYSIS Products of Electrolysis

2. ELECTROLYSIS
The Process of Chemical decomposition of the electrolyte by the passage of electricity through its molten or dissolved state

3. ELECTROLYTIC CELL Device consists of
i) Electrolytic tank It is made of glass, wood or bakelite.
ii) Electrolyte it is in dissolved state or molten state.
iii) Source of Electricity cell or battery
iv) Electrodes 2 RODS
a) Cathode electrode connected to negative terminal of battery
b) Anode electrode connected to positive terminal of battery

5. ELECTROLYTIC CELL
CATIONS Positively charged ions move towards CATHODE (-) , gain electrons and get reduced
Anions Negatively charged ions move towards ANODE(+) , lose electrons and get oxidised

6. Class XI-XII - Electrolysis of Aq. CuSO4 Using Inert Electrode - Dr
Class XI-XII - Electrolysis of Aq. CuSO4 Using Inert Electrode - Dr. Amal K Kumar.mp4

7. PRODUCTS OF ELECTROLYSIS
PRODUCTS OF ELECTROLYSIS depend on
i) Nature of Materials
ii)Type of electrode
a)INERT ELECTRODE
They act as source or sink for electrons.
They do not participate in electrode reactions.
eg)Pt,Au
b) ACTIVE ELECTRODE
They participate in the electrode reactions.
eg) Cu,Ag

8. OVER VOLTAGE
Thermodynamically faesible reactions do not seem to occur because at lower voltage they are slow. This creates electrical resistance at the electrodes. A higher potential called OVER POTENTIAL is required to make the reaction occur

9. ELECTROLYSIS OF AQUEOUS SODIUM CHLORIDE SOLUTION

10. At the Cathode At the cathode(-):
Na+(aq) + e- → Na(s) reduction Eo =-2.71 v H2O+ 2e-  ½ H2 + OH- reduction Eo = v
(l) (g) ( aq)
The reaction with higher reduction potential will take place.
So H2 gas will be formed instead of Na

11. ANODE
H2O  ½ O2 + 2H+ + 2e- Eo =-1.23 v Cl -  ½ Cl2 + e- - Eo =-1.36 v The one with lower reduction potential should take place. But because of over voltage the reduction potential of chloride ion is less and so it takes place. So Cl2 gas is liberated at anode. Na+ and OH- remain in solution.

12. ELECTROLYSIS
Electrolysis of aqueous ionic compounds (using inert electrodes)

13. INERT ELECTRODES
In the electrolysis of molten electrolytes, there are only two kinds of ions. In aqueous solutions, there are four kinds of ions; two come from the electrolyte and two from the water.
Of the four ions in an aqueous solution, only two are discharged.

14. ELECTROLYSIS OF SULPHURIC ACID
At the cathode: Hydrogen ions are discharged to produce hydrogen gas.
2H+(aq) + 2e → H2(g)
At the anode: Hydroxide ions are discharged, producing oxygen gas.
4OH-(aq) → O2(g) + 2H2O(l) + 4e-
Overall change:
2H2O(l) → H2(g) + O2(g)
Changes in solution: Only water decomposes.

15. ACTIVE ELECTRODES Electrolysis of aq. CuSO4 using copper electrodes
copper being the same element as the ions present in solution, it is a reactive electrode
The anode will take part in the reaction
the copper electrode dissolves into solution to replenish the Cu2+ ions discharged at the cathode

16. Electrolysis of aq. CuSO4 using copper electrodes
At the anode
Cu  Cu e-
copper anode dissolves
At the cathode
Cu e-  Cu
copper metal deposited

17. Electrolysis of Copper(II) Sulphate Solution using Copper Electrodes
At the cathode: Copper metal is deposited on the cathode.
At the anode: The copper in the anode is oxidised to form copper(II) ions.
Observation: The copper cathode gains copper and becomes larger. The copper anode is oxidised and becomes smaller. The amount of copper(II) sulphate and the colour of the solution do not change.