Reduction Potential

Definition

Reduction potential, also known as redox potential, is a measure of the tendency of a chemical species to acquire electrons and be reduced. It is a fundamental concept in electrochemistry and is used to predict the spontaneity and direction of redox reactions.

5 Must Know Facts For Your Next Test

1. Reduction potential values are typically measured in volts (V) or millivolts (mV) and can be positive or negative.
2. Positive reduction potentials indicate a species that is easily reduced, while negative reduction potentials indicate a species that is difficult to reduce.
3. The reduction potential of a half-reaction is determined by the ease with which the species in the half-reaction can gain electrons.
4. Reduction potentials are used to predict the spontaneity and direction of redox reactions by comparing the reduction potentials of the half-reactions involved.
5. The reduction potential of a cell is the difference between the reduction potentials of the two half-reactions occurring at the anode and cathode.

Review Questions

• Explain how reduction potential is used to predict the spontaneity and direction of redox reactions.
  • The reduction potential of a half-reaction indicates the ease with which a species can gain electrons and be reduced. By comparing the reduction potentials of the half-reactions involved in a redox reaction, it is possible to predict the spontaneity and direction of the reaction. If the difference in reduction potentials between the two half-reactions is positive, the reaction will be spontaneous and occur naturally. The half-reaction with the more positive reduction potential will be reduced, while the half-reaction with the more negative reduction potential will be oxidized.
• Describe the relationship between reduction potential and the electrochemical series.
  • The electrochemical series is a list of elements arranged in order of their standard reduction potentials. This series indicates the relative tendency of elements to be oxidized or reduced. Elements with more positive reduction potentials are more easily reduced and are higher in the electrochemical series, while elements with more negative reduction potentials are more easily oxidized and are lower in the series. The position of an element in the electrochemical series can be used to predict its behavior in redox reactions and its reactivity.
• Analyze how the reduction potential of a cell is determined and how it relates to the spontaneity of the overall redox reaction.
  • The reduction potential of a cell is the difference between the reduction potentials of the two half-reactions occurring at the anode and cathode. The cell reduction potential is calculated by subtracting the reduction potential of the anode half-reaction from the reduction potential of the cathode half-reaction. If the cell reduction potential is positive, the overall redox reaction is spontaneous and will occur naturally. The magnitude of the cell reduction potential indicates the driving force of the reaction, with a larger positive value corresponding to a more favorable and spontaneous reaction. The cell reduction potential is a crucial parameter in determining the feasibility and direction of electrochemical processes.

Related terms

Oxidation-Reduction (Redox) Reaction: A chemical reaction in which one reactant loses electrons (is oxidized) while another reactant gains electrons (is reduced).

Standard Reduction Potential:

The reduction potential of a half-reaction under standard conditions (25°C, 1 atm pressure, and 1 M concentrations of all dissolved species).

Electrochemical Series:

A list of elements arranged in order of their standard reduction potentials, which indicates their relative tendency to be oxidized or reduced.