Electrolytic cell

Definition

An electrolytic cell is an electrochemical cell that uses electrical energy to drive a non-spontaneous chemical reaction. In this type of cell, an external voltage source forces the flow of electrons through an electrolyte, resulting in chemical changes at the electrodes. This concept is crucial in understanding various electrochemical processes, including the manipulation of electrode potentials, the calculation of cell efficiencies, and the thermodynamic relationships governing these systems.

5 Must Know Facts For Your Next Test

1. Electrolytic cells are used in industrial applications such as electroplating, metal refining, and the production of chemicals like chlorine and hydrogen.
2. In an electrolytic cell, the reaction is driven by applying a voltage that exceeds the cell's equilibrium potential, allowing non-spontaneous reactions to occur.
3. The efficiency of an electrolytic cell can be affected by factors such as temperature, concentration of reactants, and the materials used for electrodes.
4. Electrolytic cells can be described using cell notation similar to galvanic cells, but with a key difference: they indicate the direction of electron flow due to external voltage.
5. Unlike galvanic cells that produce electricity from spontaneous reactions, electrolytic cells require a continuous supply of electrical energy to maintain the reaction.

Review Questions

• How does an electrolytic cell differ from a galvanic cell in terms of energy flow and reaction spontaneity?
  • An electrolytic cell differs from a galvanic cell primarily in that it requires an external voltage source to drive a non-spontaneous reaction. While galvanic cells generate electrical energy from spontaneous reactions that occur naturally, electrolytic cells convert electrical energy into chemical energy. This distinction highlights how electrolytic cells facilitate reactions that would not otherwise take place under standard conditions.
• Discuss the role of electrode potentials in determining the feasibility of reactions within an electrolytic cell.
  • In an electrolytic cell, electrode potentials play a critical role in assessing whether a reaction can occur when driven by external voltage. The Nernst equation can be utilized to calculate the potential at non-standard conditions, allowing for a comparison between applied voltage and the required potentials for oxidation and reduction reactions. If the applied voltage is greater than the required cell potential calculated from standard electrode potentials, then the desired non-spontaneous reaction will proceed.
• Evaluate how temperature and concentration affect the efficiency of an electrolytic cell during operation.
  • The efficiency of an electrolytic cell can significantly vary with temperature and concentration. As temperature increases, it typically enhances reaction kinetics, thereby improving efficiency. Higher concentrations of reactants also lead to more available ions for conduction, which can reduce resistance within the electrolyte and increase current flow. However, if either parameter is pushed too far beyond optimal conditions, it may lead to unwanted side reactions or decreased efficiency overall. Understanding these dependencies is essential for optimizing industrial electrochemical processes.

Related terms

Electrolysis: The process by which electrical energy is used to drive a chemical reaction, often occurring in an electrolytic cell.

Anode: The electrode where oxidation occurs in an electrolytic cell, typically connected to the positive terminal of the power supply.

Cathode: The electrode where reduction occurs in an electrolytic cell, usually connected to the negative terminal of the power supply.