Electrolytic cells

Definition

Electrolytic cells are electrochemical devices that use an external power source to drive a non-spontaneous chemical reaction. This process involves the decomposition of compounds, typically electrolytes, through the application of electric current, enabling the conversion of electrical energy into chemical energy. They are crucial for various applications such as electroplating, electrolysis, and the production of chemicals.

5 Must Know Facts For Your Next Test

1. Electrolytic cells require an external power supply, like a battery or a power source, to initiate the chemical reactions.
2. The reactions in electrolytic cells are non-spontaneous, meaning they do not occur naturally and need energy input.
3. During operation, cations move towards the cathode while anions move towards the anode, allowing for charge balance within the cell.
4. Electrolytic cells are widely used in industrial processes such as metal extraction and purification, and in the production of substances like chlorine and hydrogen gas.
5. The efficiency of electrolytic cells can be influenced by factors such as temperature, concentration of the electrolyte, and current density.

Review Questions

• How does the function of electrolytic cells differ from that of galvanic cells?
  • Electrolytic cells use an external power source to drive non-spontaneous reactions, while galvanic cells generate electrical energy from spontaneous chemical reactions. In electrolytic cells, reactions occur against their natural tendency, which requires input energy. In contrast, galvanic cells convert chemical energy into electrical energy without needing any external force. This fundamental difference highlights their distinct applications in various electrochemical processes.
• What role do electrodes play in electrolytic cells, particularly regarding oxidation and reduction?
  • In electrolytic cells, electrodes serve as sites for oxidation and reduction reactions. The anode is where oxidation occurs, losing electrons and resulting in a positive charge due to the external power source. Conversely, at the cathode, reduction takes place where electrons are gained. This electron transfer is essential for driving the non-spontaneous reactions characteristic of electrolytic processes and is crucial for maintaining overall charge balance within the cell.
• Evaluate how the principles governing mass transport affect the efficiency of electrolytic cells during operation.
  • Mass transport plays a significant role in determining the efficiency of electrolytic cells because it influences how reactants are delivered to the electrodes and products are removed from them. Efficient mass transport ensures that reactants remain available at the electrodes for oxidation and reduction processes. If mass transport is limited due to factors like low electrolyte concentration or slow diffusion rates, it can lead to reduced current efficiency and increased overpotential. Understanding these principles allows for optimizing conditions such as stirring or increasing temperature to enhance performance.

Related terms

Electrolysis: The process of using electrical energy to drive a chemical reaction, often used in electrolytic cells to decompose compounds.

Anode: The electrode where oxidation occurs in an electrolytic cell; it is positive due to the external power source.

Cathode: The electrode where reduction occurs in an electrolytic cell; it is negative and attracts cations from the electrolyte.