💏intro to chemistry review

key term - Electrolytic Cell

Definition

An electrolytic cell is an electrochemical cell that uses an external electrical current to drive a non-spontaneous redox reaction. It is a device that converts electrical energy into chemical energy through the process of electrolysis.

5 Must Know Facts For Your Next Test

  1. In an electrolytic cell, the external power supply forces the flow of electrons in the opposite direction of a spontaneous redox reaction.
  2. The anode in an electrolytic cell is the site of oxidation, where the less reactive species is oxidized, while the cathode is the site of reduction.
  3. The potential difference applied across the electrolytic cell must be greater than the standard cell potential of the reaction for it to occur.
  4. Electrolytic cells are used in a variety of industrial processes, such as the extraction of metals from their ores, the electroplating of metals, and the production of hydrogen and oxygen gases.
  5. The efficiency of an electrolytic cell is determined by the ratio of the actual amount of product formed to the theoretical amount predicted by Faraday's laws of electrolysis.

Review Questions

  • Explain how an electrolytic cell differs from a voltaic (galvanic) cell in terms of the direction of electron flow and the nature of the redox reaction.
    • In a voltaic (galvanic) cell, the redox reaction is spontaneous, and the flow of electrons occurs from the more reactive species (the anode) to the less reactive species (the cathode). In contrast, an electrolytic cell uses an external power supply to drive a non-spontaneous redox reaction, forcing the flow of electrons in the opposite direction, from the less reactive species to the more reactive species. This allows the electrolytic cell to perform chemical reactions that would not occur naturally, such as the decomposition of water into hydrogen and oxygen gases.
  • Describe the role of the electrochemical series in predicting the direction of electron flow in an electrolytic cell.
    • The electrochemical series, also known as the activity series or reactivity series, is a list of elements arranged in order of decreasing reactivity. This series can be used to predict the direction of electron flow in an electrolytic cell. The less reactive species at the cathode will be reduced, while the more reactive species at the anode will be oxidized. By consulting the electrochemical series, one can determine which species will be reduced or oxidized at the respective electrodes, and thus predict the overall direction of the non-spontaneous redox reaction in the electrolytic cell.
  • Analyze the factors that determine the efficiency of an electrolytic cell and explain how these factors can be optimized to improve the cell's performance.
    • The efficiency of an electrolytic cell is determined by the ratio of the actual amount of product formed to the theoretical amount predicted by Faraday's laws of electrolysis. Factors that can affect the efficiency include the potential difference applied across the cell, the concentration and purity of the electrolyte, the surface area and placement of the electrodes, and the temperature of the system. To optimize the efficiency, the potential difference applied should be just slightly higher than the standard cell potential of the reaction, the electrolyte should be highly conductive and free of impurities, the electrodes should have a large surface area and be positioned to maximize the interaction with the electrolyte, and the temperature should be maintained at an optimal level to facilitate the desired reaction kinetics. By carefully controlling these factors, the efficiency of the electrolytic cell can be maximized, making the process more economical and environmentally friendly.