The document summarizes the process of electrolysis for two types of electrolytes: molten sodium chloride and aqueous electrolytes. For molten sodium chloride, sodium and chloride ions move to the cathode and anode, respectively, where they are discharged. Sodium forms at the cathode while chlorine gas forms at the anode. For aqueous electrolytes like dilute sulfuric acid, hydrogen, sulfate, and hydroxide ions are present and migrate to the electrodes where hydrogen gas forms at the cathode and oxygen gas forms at the anode.

1. ELECTROLYSIS MOLTEN SODIUM CHLORIDE
[Solid ionic compounds do not conduct electricity because their ions are held in
fixed positions by strong electrostatic forces]
[Aqueous electrolytes conduct electricity because their ions move freely]
a) Ions in the electrolyte are Sodium ions and Chloride ions
b) Sodium ions (Cations) are attracted to the cathode while Chloride ions
are attracted to the anode
c) Reaction at the cathode: Na+ + e Na
Explanation: Each sodium ion gains one electron to form sodium atom.
Sodium ions are discharged
Reaction at the anode: 2Cl- Cl2 + 2e
Explanation: Each chloride ion loses one electron to form chlorine atom.
Two chlorine atoms will combine to form Cl2 molecule
d) Observation
Cathode: Shiny silvery deposits are formed
Anode: greenish-yellow bubbles gas are eventually liberated
e) Overall reaction
2 Na+ + 2Cl- Cl2 + 2Na
ELECTROLYSIS OF AQUEOUS ELECTROLYTES
• Aqueous electrolytes are mixtures of two electrolytes – the compound and
water
• Water ionises to give H+ and OH- as follows:
H2O H+ + OH-
• More than one type of anion and cation are present
• Example: Electrolysis of dilute Sulphuric acid
H2SO4 2H+ + SO42-
H2O H+ + OH-
• Sulphuric acid dissolves in water to form H+, SO42- and OH- ions

2. a) Ions in the electrolyte: H+, SO42- and OH-
b) SO42- and OH- ions migrate to the cathode while H+ ions migrate to the
anode
c) Reaction at the cathode:
OH- ions are preferentially discharged
4OH- 2H2O + O2 + 4e
Explaination: Each OH- ion loses one electron to form oxygen gas
and water.
Reaction at the anode:
2H+ + 2e H2
Explanation: Each H+ ion gains one electron to form hydrogen atom.
Two hydrogen atoms will join together to form H2 molecule
d) Observation
Cathode: Colourless bubbles gas are formed
Validity test:
[To confirm the presence of gas is: place in the burning splinter into
the test tube, gas burns with a ‘pop’ sound]
Anode: Colourless bubbles are formed
Validity test:
[To confirm the presence of gas is: place in the glowing splinter into
the test tube, gas rekindles glowing splinter]