Question

In the electrochemical cell, flow of electrons is from (a) cathode to anode in the solution (b) cathode to anode through external supply (c) cathode to anode through internal supply (d) anode to cathode through internal supply

Short answer

The correct answer is (d) Anode to cathode through internal supply.

Step-by-step solution

Identifying anode and cathode

In an electrochemical cell, the anode is the electrode where oxidation (loss of electrons) happens and the cathode is the electrode where reduction (gain of electrons) occurs.

Determining electron flow direction

Since oxidation occurs at the anode, electrons flow from the anode to the cathode in the external circuit.

Eliminating incorrect options

From understanding the electron flow, it is clear that electrons do not move from cathode to anode (this eliminates options a, b and c). Therefore, the only possible answer is d - 'anode to cathode through internal supply'.

Key concepts

Understanding the Anode

In an electrochemical cell, the anode is a crucial component where oxidation occurs. Oxidation refers to the loss of electrons by a substance. As a result, the anode is the site where this electron removal begins. Because oxidation happens here, it is characterized by having a negative charge.
When substances lose electrons, these electrons need to go somewhere. This is essential for the flow of electrical current. To support this action, the material of the anode must be good at conducting electricity.
The anode's importance is linked closely to its function in driving the electrochemical reactions forward. Its position within the cell determines how the entire system will behave and operate efficiently.

Function of the Cathode

The cathode in an electrochemical cell bears the responsibility of hosting reduction reactions. Reduction is the process through which a material gains electrons. Consequently, the cathode usually carries a positive charge because electrons are added to it.
This positive charge attracts the electrons that flow from the anode, making the cathode an essential component for completing the circuit within the cell. Thus, the movement of electrons leads to the flow of current in an electrical circuit.
Materials chosen for the cathode also need to be efficient conductors. This ensures that they can facilitate the movement of electrons effectively to maintain the cell's function.

Pathway of Electron Flow

Electron flow is a fundamental aspect of how electrochemical cells operate. As electrons are released by oxidation at the anode, they travel through an external circuit towards the cathode where reduction occurs. This completely contradicts the options that suggest electrons move from the cathode to anode.
Understanding electron flow is crucial because it dictates how electrical energy is converted and used in a cell. It is essential to note that this flow creates an electric current which can be harnessed to do work in external devices.
Moreover, ensuring that the setup directs electron flow correctly is vital for creating efficient and functional cells in various applications such as batteries and fuel cells.