1. THE ELECTROLYSIS OF AQUEOUS SOLUTION
Identify cations and anions in various salt solutions
Describe the electrolysis of an aqueous solution
Predict the products of electrolysis of aqueous solutions
Write half equations for discharge of ions at the anode and the cathode

2. Molten Salts vs. Salt Solutions

4. Universal indicator-pH by color

5. Anode cathode electrolyte Anions Cations ELECTROLYTIC CELL + - + - + -

6. Step to identify ion in electrolysis of aqueous solution
1. Identify all ion present in aqueous solution
2. Identify ion moving to
cathode and anode electrode
3. Identify the ion that will be discharge
in cathode and anode
4. Write half equation in cathode and anode

7. 1. Identify all ion present in aqueous solution
NaCl Solution
Na+ H+
Cl-
OH-

8. Sodium Chloride Solution1
Carbon-inert
Na+
Sodium Chloride Solution H+
Na+
OH-
Cl- H+
Cl-
Cl-
OH-
Electrolysis of HCl aqueous

9. 2. Identify ion species moving to cathode and anode electrode
NaCl Solution H+
Na +
Cl-
OH-
cathode
anode

10. Electrochemical Series
CATIONS
ANIONS K+ F-
Na+
SO42-
Ca+
NO3-
Mg+
Cl-
Al+
Br -
Zn+ I-
Fe+
OH-
OH-
Sn+
Pb+ H+
MORE EASY TO DISCHARGE
Cu+
Ag+

11. NaCl Solution 3. Identify the ion species that will be discharged
in cathode and anode
NaCl Solution H+
Cl-
OH-
Na+
cathode
anode
Choose the ions that are lower
in the electrochemical series.
They are the ions most easily discharged

12. 4. Write half equation in cathode and anode
NaCl Solution H+
Cathode:
2H+ + 2e H2
OH-
Anode:
4OH H2O + O2 + e

13. STEP TO WRITE HALF EQUATION OF DISCHARGE ION
1. Write the reactant and product of reaction
2. Balance the number of atoms
in both equations
3. Balance the charge of both equation
by adding electrons

14. Salt in SOLUTION Anode Cathode NaCl with UI NaCl Concentrated
Observations
Salt in SOLUTION
Anode
Cathode
NaCl with UI
Gas bubble are released. A colorless gas is formed and the universal indicator turns red
Gas bubbles are released. A colorless gas is formed which turns the universal indicator purple
NaCl Concentrated
Without UI
A greenish-yellow gas with a swimming pool smell. The gas turns the blue litmus paper red and then white.
Gas bubles are released. A colourless gas which burns with a pop sound is produced.

15. Dry Cell Battery Interior