Question

Which of the following statements is correct about Galvanic cell ? (a) It converts chemical energy into electrical energy. (b) It converts electrical energy into chemical energy. (c) It converts metal from its free state to the combined state. (d) It converts electrolyte into individual ions.

Short answer

Option (a) is correct, as a Galvanic cell converts chemical energy into electrical energy.

Step-by-step solution

Understanding Galvanic Cells

A Galvanic cell, also known as a voltaic cell, is a device that converts chemical energy into electrical energy through a spontaneous redox reaction. In a simple Galvanic cell setup, there are two different metals connected by a salt bridge or porous membrane, and each metal is immersed in a solution containing its own ions. As the chemical reaction occurs, electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs), generating an electric current.

Analyzing the Options

Option (a) states that a Galvanic cell converts chemical energy into electrical energy, which is consistent with the principle of operation of a Galvanic cell. Option (b) incorrectly refers to the conversion of electrical energy into chemical energy, which is characteristic of an electrolytic cell, not a Galvanic cell. Option (c) is misleading as it suggests a transformation that isn't typical for the operation of a Galvanic cell. Option (d) is incorrect because while ions do move in a Galvanic cell, the cell doesn't convert the electrolyte into ions; the ions are already present in the solutions around the electrodes.

Choosing the Correct Statement

From analyzing all the options and understanding the operation of a Galvanic cell, we identify that option (a) is the correct statement, as it accurately describes the primary function of a Galvanic cell - converting chemical energy into electrical energy.

Key concepts

Chemical Energy to Electrical Energy Conversion

The magic of a Galvanic cell lies in its ability to transform chemical energy into electrical energy. But how does this seemingly mystical process occur? Imagine two chemical substances with a yearning to react with each other, similar to two friends separated by a distance. When these substances are placed in a Galvanic cell, they can finally interact through a chemical reaction. During this reaction, electrons are released from one substance and absorbed by the other. This movement of electrons creates electricity, much like sending messages between the two friends.The electrical energy produced can then power a light bulb, turn a motor, or charge a battery - it’s like the two friends finally meeting and creating amazing memories.

Redox Reaction

Redox reactions are the heart and soul of a Galvanic cell. The term 'redox' is a portmanteau of reduction and oxidation, these are the two halves of this fundamental dance. During oxidation, a substance loses electrons, like a tree shedding its leaves in the autumn. Conversely, reduction is the gaining of electrons, akin to a sponge soaking up water. In the context of our Galvanic cell, one electrode (the anode) undergoes oxidation, while the other electrode (the cathode) experiences reduction. It’s a give and take relationship that results in the flow of electrons through the circuit, powering our devices and illuminating our homes.

Electrolytic Cell vs Galvanic Cell

So, what's the difference between an electrolytic cell and a Galvanic cell? It's like comparing a battery being charged (electrolytic cell) to a battery powering a remote control (Galvanic cell).

In an electrolytic cell, electrical energy is the initial input, providing the spark that drives the chemical reaction. This is often used to decompose chemical compounds or plate one metal onto another - think of it as forcing the two aforementioned 'friends' to exercise.

On the flip side, a Galvanic cell spontaneously converts chemical energy into electrical energy without any external electrical input needed. It’s a natural meeting of substances resulting in the release of energy. So, while both types of cells are vital players in the world of chemistry and electricity, they operate on essentially opposite principles.

Electron Flow in Electrochemical Cells

Electron flow is the lifeline of electrochemical cells, much like a river carrying water through the landscape. In both an electrolytic and a Galvanic cell, electrons move through the external circuit. However, the direction and the driving force behind this movement are different for each type of cell. In a Galvanic cell, electrons move from the anode to the cathode due to the natural tendency of the chemical reaction occurring - it’s all spontaneous, no external push needed.

In an electrolytic cell, however, an external source of energy propels electrons to move from the cathode to the anode. It’s like paddling against the current - it takes work.

Regardless of the type of cell, the movement of electrons is critical. They are the couriers in the world of electrochemistry, delivering energy from one place to another, enabling the reactions and functions we rely on daily.