Electrolytic cells concept questions and answers

  1. What is an electrolytic cell?

    An electrolytic cell is a type of electrochemical cell that drives a non-spontaneous redox reaction through the application of electrical energy.

  2. How does an electrolytic cell differ from a galvanic cell?

    While a galvanic cell converts chemical energy into electrical energy through a spontaneous redox reaction, an electrolytic cell uses electrical energy to drive a non-spontaneous redox reaction.

  3. What happens at the anode and the cathode in an electrolytic cell?

    At the anode (which is positively charged in an electrolytic cell), oxidation occurs, meaning electrons are lost. At the cathode (which is negatively charged in an electrolytic cell), reduction occurs, meaning electrons are gained.

  4. What is the role of the electrolyte in an electrolytic cell?

    The electrolyte provides ions that flow in the solution, allowing current to pass through the cell.

  5. What is the Faraday’s law of electrolysis?

    Faraday’s law of electrolysis states that the amount of a substance produced at an electrode during electrolysis is directly proportional to the number of moles of electrons (the quantity of electricity) transferred at that electrode.

  6. What is an application of electrolytic cells?

    Electrolytic cells are used in electroplating, where a thin layer of metal is deposited onto an object, and in electrolysis processes such as the production of aluminum from its ore.

  7. Why is the anode positive in an electrolytic cell?

    In an electrolytic cell, the anode is positive because it is connected to the positive terminal of the power source. This is where oxidation takes place as electrons are being pushed away by the power source.

  8. How does the energy change in an electrolytic cell?

    In an electrolytic cell, electrical energy from an external source is converted into chemical energy stored in the products of the reaction.

  9. What is meant by overpotential in an electrolytic cell?

    Overpotential is the extra voltage required, over and above the theoretical voltage, to bring about electrolysis. It is due to factors such as the activation energy for the reaction and resistance in the circuit.

  10. What does the term “electrolysis” mean?

Electrolysis is the process of driving a chemical reaction by passing an electric current through an electrolyte. The reaction is non-spontaneous and is facilitated by an electrolytic cell.

  1. What is an example of a substance that can be broken down by electrolysis?

Water can be broken down into hydrogen and oxygen gas through the process of electrolysis.

  1. What is the equation to calculate the amount of substance produced in electrolysis according to Faraday’s law?

The equation is m = (M x I x t) / (n x F) where m is mass of substance produced, M is molar mass of the substance, I is the current in amperes, t is time in seconds, n is the number of electrons transferred in the redox reaction, and F is the Faraday constant.

  1. What is the role of the battery or external power source in an electrolytic cell?

The battery or external power source provides the energy required to drive the non-spontaneous redox reaction in an electrolytic cell.

  1. Can an electrolytic cell operate without the external power source?

No, an electrolytic cell cannot operate without an external power source because the redox reaction it facilitates is non-spontaneous.

  1. Why is there a need to keep the electrolyte solution stirred in an electrolytic cell?

Keeping the electrolyte solution stirred ensures that the concentration of the electrolyte remains uniform throughout the solution. This allows the cell to operate more efficiently.

  1. What would happen if the electrodes in an electrolytic cell were reversed?

If the electrodes were reversed, the reactions at the electrodes would also reverse. The anode would become the cathode and vice versa.

  1. What are the products of the electrolysis of water?

The products of the electrolysis of water are hydrogen gas at the cathode and oxygen gas at the anode.

  1. What are the bubbles observed during electrolysis?

The bubbles observed during electrolysis are usually gases produced at the electrodes. The specific gas depends on the substance being electrolyzed.

  1. What is the role of the salt bridge in a galvanic cell and does an electrolytic cell need one?

The salt bridge in a galvanic cell maintains electrical neutrality by allowing ions to flow between the half-cells. An electrolytic cell does not require a salt bridge because the half-reactions occur at electrodes immersed in the same solution.

  1. What would happen to an electrolytic cell if the external power source was disconnected?

If the power source was disconnected, the electrolytic cell would stop operating because the redox reaction in an electrolytic cell is non-spontaneous and requires a continuous input of energy.