19.5.1 Electrolytic Cells

Question 1

Electrolytic Cells

Answer 1

• The simplest type of electrolytic cell is one in which the electrolyte, the solvent, and the reactants are all the same substance.
• In electrolysis of aqueous solutions, the water must be considered when determining the electrode half-reactions.
• Electrolytic cells can be used to plate metals onto surfaces.

Question 2

note

Answer 2

• The simplest type of electrolytic cell is one in which the electrolyte, the solvent, and the reactants are all the same substance.
• This can be accomplished by melting an ionic salt. While solid ionic salts do not conduct electricity, molten ionic salts do conduct electricity.
• This process is used in the Downs cell, in which molten sodium chloride is electrolyzed to produce chlorine gas (at the anode) and sodium metal (at the cathode).
• In aqueous solutions, the water must be considered when determining electrode half-reactions.
• In the electrolysis of aqueous sodium chloride, the
  standard reduction potential for the reduction of sodium cation is much lower than for the reduction of water. For this reason, hydrogen gas is produced at the cathode of this cell.
• However, the standard oxidation potential for the oxidation of chloride ion is close to the standard oxidation potential for the oxidation of water. If the concentration of chloride ion is kept high, the Nernst equation predicts that this potential will be higher, and the reaction will proceed.
• Electrolytic cells can be used to plate metals onto surfaces. In order for the metal half-reaction to proceed, the reduction potential for the metal cation must be higher than that of water.

Question 3

Which of the following is not produced by the electrolysis of aqueous NaCl?

Answer 3

Na

Question 4

Which of the following is a commercial product in an electrolytic cell with an aqueous solution of NaCl?

Answer 4

NaOH

Question 5

In the diagram of an electrolytic cell, which is the anode?

Answer 5

A

Question 6

Which of the following is the most easily oxidized?

Answer 6

Mg2+ + 2e- -> Mg E = -2.37 V

Question 7

By which process is electricity used to bring about a chemical change?

Answer 7

Electrolysis

Question 8

Which of the following is the product of oxidation in an electrolytic cell with molten NaCl?

Answer 8

chlorine gas

Question 9

Where does oxidation occur in an electrolytic cell?

Answer 9

Anode

Question 10

Which of the following is the product of reduction in an electrolytic cell with molten NaCl?

Answer 10

Na

Question 11

Given the following reduction potentials, which is most easily reduced?

Answer 11

Au3+ + 3e- -> Au E = 1.50 V

Question 12

Which of the following is the product of oxidation in an electrolytic cell with a concentrated aqueous solution of NaCl?

Answer 12

Cl2