17.3 Standard Reduction Potentials

17.3 Standard Reduction Potentials

• The oxidation of magnesium to magnesium ion occurs in the beaker on the left side, while the reduction of hydrogen to hydrogen occurs in the beaker on the right.
• The left beaker has electrons moving into the right beaker.

• It is not possible to determine the electrical potential of a single electrode, but we can assign it a value of zero and use it as a reference.
• The SHE consists of 1 atm of hydrogen gas bubbled through a 1 M HCl solution.
• Platinum is used as the electrode.
• For all temperatures, the voltage is zero.

• The electrode is used with HCl.
• H+ is added to the solution to produce hydrogen gas.

• Reduction is the reverse of oxidation.

• A galvanic cell can be used to determine the standard reduction potential.

• Other standard reduction potentials can be determined using the SHE as a reference.
• Reduction is the reverse of oxidation.

• The SHE is not often used in the laboratory.
• It established the zero for standard reduction potentials.
• Reduction potentials for selected reactions are shown.
• The standard reduction potential of Ag+ can be determined by using a galvanic cell.
• The SHE on the left has a standard reduction potential of zero.

• It is possible to determine the standard cell potential for many oxidation-reduction reactions with tables like this.

• The oxidizing and reducing agents should be identified.

• Positive cell potentials and all the reduction reactions can be reversed.
• The half-reaction will have a negative standard reduction potential.