1. The Electrolytic Cell

2. In the electrolytic cell, a nonspontaneous redox reaction is forced to occur by the use of a source of electricity. In the electrolytic cell, electrons are FORCED to flow from the positive electrode to the negative electrode! In the electrolytic cell, the cathode has a negative charge and the anode has a positive charge!

3. The Electrolytic Cell Electrolytic cells are used to purify highly reactive elements from their compounds! Na 0 (sodium) never exists pure in nature! Pure sodium can be extracted from NaCl by using an electrolytic cell.

4. The Electrolytic Cell Ex.1) Electrons always flow out of the negative pole of an electric source such as a battery. Electrons always flow towards the cathode. battery + - NaCl ( l ) e-e- cathodeanode Put a + on the positive electrode and a - on the negative electrode. + -

5. The Electrolytic Cell Ex.1) Write the reduction half reaction: ______________________ Write the oxidation half reaction: ______________________ battery + - NaCl ( l ) e-e- cathodeanode Cl 1- →Cl 2 0 + 2 e - 2 Na 1+ →Na 0 + 1 e - 222 +1 NaCl 2 00

6. The Electrolytic Cell Ex.1) _______________________________ [write the balanced redox reaction] battery + - NaCl ( l ) e-e- cathodeanode +1 NaCl 2 00 Na 1+ Na 0 Cl 1- →Cl 2 0 222++

7. The Electrolytic Cell Ex.1) a)The electrode on the left is the ____ode and the electrode on the right is the ____ode. battery + - NaCl ( l ) e-e- +1 NaCl 2 00 an cath

8. The Electrolytic Cell Ex.1) b)The positive electrode is on the __________ and the negative electrode is on the __________. battery + - NaCl ( l ) e-e- +1 NaCl 2 00 left right

9. The Electrolytic Cell Ex.1) c)Write the half reaction that occurs at the electrode on the left. battery + - NaCl ( l ) e-e- +1 NaCl 2 00 _________________________________________ Cl 1- →Cl 2 0 + 2 e - 2

10. The Electrolytic Cell Ex.1) d)Write the half reaction that occurs at the electrode on the right. battery + - NaCl ( l ) e-e- +1 NaCl 2 00 _________________________________________ Na 1+ →Na 0 + 1 e -

11. The Electrolytic Cell Ex.2) Electrons always flow out of the negative pole of an electric source such as a battery. Electrons always flow towards the cathode. battery + - KBr ( l ) e-e- cathodeanode Put a + on the positive electrode and a - on the negative electrode. + -

12. The Electrolytic Cell Ex.2) Write the reduction half reaction: ______________________ Write the oxidation half reaction: ______________________ battery Br 1- →Br 2 0 + 2 e - 2 K 1+ →K0K0 + 1 e - 222 +1 KBr 2 00 cathodeanode e-e- KBr ( l ) - +

13. The Electrolytic Cell Ex.2) _______________________________ [write the balanced redox reaction] battery +1 KBr 2 00 K 1+ K0K0 Br 1- →Br 2 0 222++ e-e- cathodeanode KBr ( l ) - +

14. The Electrolytic Cell Ex.2) a)The electrode on the left is the ____ode and the electrode on the right is the ____ode. battery +1 KBr 2 00 - + KBr ( l ) cath an

15. The Electrolytic Cell Ex.2) b)The positive electrode is on the __________ and the negative electrode is on the __________. battery +1 KBr 2 00 e-e- KBr ( l ) - + right left

16. The Electrolytic Cell Ex.2) c)Write the half reaction that occurs at the electrode on the left. battery +1 KBr 2 00 e-e- - + KBr ( l ) _________________________________________ K 1+ →K0K0 + 1 e -

17. The Electrolytic Cell Ex.2) d)Write the half reaction that occurs at the electrode on the right. battery +1 KBr 2 00 + e-e- - KBr ( l ) _________________________________________ Br 1- →Br 2 0 + 2 e - 2

18. The Electrolytic Cell Ex.3) Electrons always flow out of the negative pole of an electric source such as a battery. Electrons always flow towards the cathode. battery + - H2O(l)H2O(l) e-e- cathodeanode Put a + on the positive electrode and a - on the negative electrode. + -

19. The Electrolytic Cell Ex.3) _______________________________ [write the balanced redox reaction] battery +1-2 H2H2 O2O2 00 H2OH2OH20H20 →O20O20 22+ e-e- cathodeanode - + H2O(l)H2O(l)

20. The Electrolytic Cell Ex.3) a)The electrode on the left is the ____ode and the electrode on the right is the ____ode. battery +1-2 00 - + H2O(l)H2O(l) H2H2 O2O2 cath an

21. The Electrolytic Cell Ex.3) b)The positive electrode is on the __________ and the negative electrode is on the __________. battery +1-2 00 e-e- - + H2O(l)H2O(l) H2H2 O2O2 right left

22. The Electrolytic Cell Ex.3) c)What substance is produced at the electrode on the left? ____________________ battery +1-2 00 e-e- - + H2O(l)H2O(l) H2H2 O2O2 Hydrogen gas

23. The Electrolytic Cell Ex.3) d)What substance is produced at the electrode on the right? ____________________ battery +1-2 00 e-e- - + H2O(l)H2O(l) H2H2 O2O2 Oxygen gas

24. The Electrolytic Cell Ex.3) e)Why must a small amount of electrolyte (such as an acid) be added to the water in order for the electrolytic decomposition to work? ________________________ ___________________________________________ battery +1-2 00 e-e- - + H2O(l)H2O(l) H2H2 O2O2 because pure water does not conduct electricity, so an electrolyte is added.

25. The Electrolytic Cell Ex. (4) Which half-reaction correctly represents the reduction of a potassium ion? (1) K + + e - → K(3) K + → K + e - (2) K + e - → K + (4) K → K + + e - Ex. (5) Given the equation: 2 Al + 3 Cu 2+ → 2 Al 3+ + 3 Cu The oxidation half-reaction is (1) Al → Al 3+ + 3e - (3) Al + 3e - → Al 3+ (2) Cu 2+ + 2e - → Cu(4) Cu 2+ → Cu + 2e -

26. The Electrolytic Cell Ex. (6) During the electrolysis of molten cesium chloride (CsCl), pure cesium is produced at the (1) positively charged cathode and pure chloride gas is produced at the negatively charged anode (2) negatively charged cathode and pure chloride gas is produced at the positively charged anode (3) positively charged anode and pure chloride gas is produced at the negatively charged cathode (4) negatively charged anode and pure chloride gas is produced at the positively charged cathode

27. The Electrolytic Cell Ex. (7) Given the voltaic cell: Pb (s) + Cu 2+ (aq) → Pb 2+ (aq) + Cu (s) The electrons will flow from (1) the Pb (s) electrode to the Cu (s) electrode (2) the Cu (s) electrode to the Pb (s) electrode (3) the Pb 2+ (aq) electrode to the Cu (s) electrode (4) the Cu 2+ (aq) electrode to the Pb (s) electrode Ex. (8) What is conserved during all chemical reactions? (1) mass, only(3) both mass and charge (2) charge, only(4) neither mass nor charge

28. + Battery - e-e- Molten NaCl (ℓ) e-e- Na + Cl - Cl 2 0 Na 0 CathodeAnode - + 2 NaCl  2 Na + Cl 2 Reduction: 2 Na +1 + 2e-  2 Na 0 Oxidation: 2 Cl -1  Cl 2 0 + 2 e- Na 0 The Electrolytic Cell Na 0 Molten Na (ℓ) Na 0

29. + Battery - e-e- aqueous CuBr 2(aq) e-e- Cu +2 Br - H2OH2O Br 2 0 Cu 0 CathodeAnode - + CuBr 2  Cu + Br 2 Reduction: Cu +2 + 2e-  Cu 0 Oxidation: 2 Br -1  Br 2 0 + 2 e- Br - H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O The Electrolytic Cell

30. - Battery + e-e- H 2 O (ℓ) e-e- H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H20H20 O20O20 Anode Cathode + - 2 H 2 O  2 H 2 + O 2 Reduction: 4 H +1 + 4e-  2 H 2 0 Oxidation: 2 O -2  O 2 0 + 4 e- H20H20 O -2 H +1 The Electrolytic Cell