Question

The electrode through which electrons enter the electrolytic solution is (a) cathode (b) anode (c) may be anode or cathode (d) both, anode and cathode

Short answer

The electrode through which electrons enter the electrolytic solution is (a) cathode.

Step-by-step solution

Understand the process of electrolysis

Electrolysis is a chemical process where electrical energy is used to drive a non-spontaneous reaction. During this process, an electrolytic solution contains ions that move towards the electrodes, where reduction or oxidation occurs.

Identify the electrodes

In an electrolytic cell, there are two electrodes called the anode and the cathode. The anode is the electrode where oxidation occurs (loss of electrons), and the cathode is the electrode where reduction takes place (gain of electrons).

Determine the correct electrode

Since the question specifies the electrode through which the electrons enter the solution, we are looking for the electrode where reduction occurs. Reduction is a gain of electrons, hence the electrons enter the electrolytic solution at the cathode.

Key concepts

Electrolytic Cell

An electrolytic cell is a type of electrical cell that uses electricity to drive a chemical reaction that otherwise would not occur spontaneously. This is in contrast to galvanic or voltaic cells, where the chemical reaction produces electricity. In an electrolytic cell, the process is essentially reversed, using electrical energy to cause a chemical change.

The primary components of an electrolytic cell include two electrodes (the anode and cathode) and an electrolyte, which is a substance containing free ions and can be either a molten salt or an aqueous solution. When a direct current is applied, ions in the electrolyte travel to their respective electrodes; cations (positively charged ions) move to the cathode to gain electrons, while anions (negatively charged ions) move to the anode to lose electrons.

Key Features of Electrolytic Cells

• An external voltage source is necessary to drive the reaction.
• Reduction occurs at the cathode, and oxidation occurs at the anode.
• Substances that may not naturally react are forced to change due to the input of electrical energy.

Electrochemical Reaction

An electrochemical reaction involves the transfer of electrons from one chemical species to another. These reactions are at the heart of electrolysis, where they are facilitated by the use of an external electrical current. Within the context of an electrolytic cell, the chemical change results from the direct passage of electric current through the electrolyte.

Electrochemical reactions are categorized as either oxidation or reduction, depending on whether electrons are being lost or gained by a substance. These reactions play a crucial role in numerous industrial applications, including metal plating, battery charging, and the production of various chemicals.

The Role of Ions and Electrodes

• Ions in an electrolyte migrate towards electrodes that have opposite charges.
• The reactions at the electrodes transform the ions into neutral atoms or molecules.
• Electrochemical reactions are used to purify metals, produce chlorine, and split water into oxygen and hydrogen.

Oxidation and Reduction

Oxidation and reduction are two halves of a type of chemical reaction called a redox reaction. Oxidation refers to the loss of electrons by a molecule, atom, or ion. Conversely, reduction describes the gain of electrons. It's important to remember the mnemonic 'OIL RIG' - Oxidation Is Loss, Reduction Is Gain - to keep track of what happens to electrodes in an electrolytic cell.

During the electrolysis process, as electrons are channeled into the electrolytic cell, they are received by the cathode, making it the site of reduction. The anode, on the other hand, sees the loss of electrons from the substances that are oxidized there. The entire electrolytic process depends on the continuous movement of electrons from the anode, through the power source, and then to the cathode.

Importance of Oxidation and Reduction in Electrolysis

• Oxidation and reduction reactions occur at the anode and cathode, respectively.
• These reactions change the composition of the electrolyte by converting ions to neutral atoms or molecules.
• Oxidation and reduction are key for processes such as energy storage and corrosion prevention.