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Learn about electrolytic cells, their components, and how they are used in processes like electrolysis of salts and electroplating. Explore the differences and similarities with voltaic cells.
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Electrolytic Cells Aim: Write half reactions for electrolysis of a salt and electroplating
What is an Electrolytic Cell? Electrolytic Cell:A cell where a battery forces a redox reaction to occur (non-spontaneous reaction). Opposite of a voltaic cell. Uses: 1) To obtain group 1 and group 2 metals. Electrolysis of salts, "Salt splitting". 2) Electroplating: plating a metal on top of another (Ex. Gold plated jewelry)
Parts of an Electrolytic Cell Electrolytic cells have only one cell. Electrolytic cells are powered by a battery or power source. Converts electrical to chemical energy. Anode- still the site of oxidation. Assigned as the POSITIVE electrode. Cathode- still the site of reduction. Assigned as the NEGATIVE electrode.
Electrolysis of a Salt Molten salt breaks up into ions in solution NaCl(l) → ________________ Na+ is attracted to negative cathode and is reduced _______________________ Cl1- is attracted to the positive anode and is oxidized ________________________
Example: Electrolysis of a Salt Write the oxidation and reduction 1/2 reaction for the following cell: ox 1/2: red 1/2: MgF2 (l)
Electroplating The metallic ions in solution with positive charge attract to the negative cathode and reduce onto it (plating). ______________________ The metal anode is oxidized to produce more positive metal ions in solution to continue the process. ______________________ - + *Negative ions do not play a part in the electroplating
Example: Write the oxidation and reduction half reactions for the plating of the Al glasses from by the Au ox 1/2: red 1/2: + - AuNO3
Similarities Between Voltaic and Electrolytic Cells 1) Both use redox reactions 2) The anode is the site of oxidation 3) The cathode is the site of reduction 4) The electrons flow through the wire from anode to cathode
Differences Between Voltaic and Electrolytic Cells Voltaic Electrolytic Non-spontaneous reaction - forced through use of a battery Anode is positive Cathode is negative One Cell Spontaneous redox reaction Anode isnegative Cathode is positive Two Half Cells
Electrolysis of a Salt a) MgCl2 ox 1/2: red 1/2: MgCl2 (l) KBr (l) a) KBr2 ox 1/2: red 1/2:
Electrolysis of a Salt c) CaO ox 1/2: red 1/2: CaO (l)
Electroplating a) ox 1/2: red 1/2: Zn ZnCl2 (aq) b) ox 1/2: red 1/2: Mn Mn(NO3)4 (aq)