Electrolysis of aqueous solution

Electrolysis of aqueous solution

1.     Electrolysis of potassium nitrate solution, KNO₃ using carbon electrodes.

	Anode (+)	Cathode (-)
Ion presents	NO-3, OH-	K+, H+
Half equation	4OH- → 2H2O + O2 +4e	2H+ + 2e → H2
Observation	Colourless gas bubbles are released	Colourless gas bubbles are released
Product	Oxygen gas	Hydrogen gas

2.     Electrolysis of silver nitrate solution, AgNO₃ using carbon electrodes.

	Anode (+)	Cathode (-)
Ion presents	NO-3, OH-	Ag+, H+
Half equation	4OH- → 2H2O + O2 +4e	Ag+ + e → Ag
Observation	Colourless gas bubbles are released	A grey solid is formed
Product	Oxygen gas	Silver metal

3.     Electrolysis of copper(II) sulphate solution, CuSO₄ using carbon electrodes.

	Anode (+)	Cathode (-)
Ion presents	SO2-4, OH-	Cu2+, H+
Half equation	4OH- → 2H2O + O2 +4e	Cu2+ + 2e → Cu
Observation	Colourless gas bubbles are released	Brown solid is formed
Product	Oxygen gas	Copper metal

4.     Electrolysis of concentrated potassium chloride solution, KCl using carbon electrodes.

	Anode (+)	Cathode (-)
Ion presents	Cl- , OH-	K+, H+
Half equation	Cl- → Cl2 + 2e	2H+ + 2e → H2
Observation	Greenish-yellow gas bubbles are released	Colourless gas bubbles are released
Product	Chlorine gas	Hydrogen gas

5.     Electrolysis of silver sulphate solution, Ag₂SO₄ using silver electrode as anode and carbon electrode as cathode.

	Anode (+)	Cathode (-)
Ion presents	-
Half equation	Ag→ Ag+ +e	Ag+ + e → Ag
Observation	Silver electrode corrodes and become thinner	A grey solid is deposited and electrode becomes thicker.
Product	Silver ion	Silver metal

6.     Electrolysis of copper(II) nitrate solution, Cu(NO₃)₂ using copper electrode as anode and carbon electrode as cathode.

	Anode (+)	Cathode (-)
Ion presents	-	-
Half equation	Cu → Cu2+ +2e	Cu2+ + 2e → Cu
Observation	Copper electrode corrodes and become thinner	Brown solid is deposited and electrode becomes thicker.
Product	Copper(II) ion	Copper metal