Concentration Cell

Introduction

The concentration cell is indeed a sort of galvanic cell in which both halves of the cell contain relatively similar electrolytes although with varying concentrations. This is used in association with the electrodes. When obtaining chemical equilibrium, such cells produce a slight voltage difference. These are accomplished by moving electrons from either the lower to the higher concentration cell. Since the electrodes of such a concentration cell seem to be the same, its standard electrode potential becomes 0. However, as the ion concentrations fluctuate, maybe there could be a potential difference between the 2 half-cells. The Nernst Equation may be used to calculate this voltage difference.

What is a Concentration Cell?

A concentration cell is composed of electrolytic as well as an electrochemical cell that has been made up of 2 half-cells. Each half-cell contains identical electrodes, but their concentrations differ at the same time. And the more concentrated half-cell gets diluted, while the lower concentration half-cell seems to have its concentration boosted by electron transfer among such two half cells. It would be completed as the cell's overall goal is to achieve chemical equilibrium. For instance, Compare 2 solutions with identical electrolytes that are linked by a salt bridge. Whenever 2 plates of a similar metal are immersed individually into the specified two solutions, the entire setup is determined to function only as the galvanic cell.

Explain the Working of the Concentration Cell

A concentration cell is formed by 2 half-cells with identical electrodes but different electrolyte concentrations. The functioning of such a concentration cell is dependent on the maintenance of equilibrium among the concentrations of 2 cells. It correspondingly concentrates more and more dilute solutions. By transferring electrons, it achieves equilibrium among the 2 half-cells. Electrons would be moved from either a lower concentration half-cell to a higher concentration half-cell. The cell's electromotive force may be calculated as follows −

$$\mathrm{E^{0}_{cell}\:=\:E^{0}_{cathode}\:-\:E^{0}_{anode}}$$

Once the cell achieves equilibrium, it produces a voltage that could be calculated from the Nernst equation as follows −

$$\mathrm{E^{0}_{cell}\:=\:E^{0}_{cell}\:-\:\frac{0.0592}{n}\log\:Q}$$

Where

$E^{0}$ is a cell's standard reduction potential.

The no. of electrons exchanged is denoted by n.

𝑄 denotes the reaction quotient

Two beakers holding electrolytic solutions of 𝐶𝑢𝑆𝑂4 as well as 𝑍𝑛𝑆𝑂4 are used in this experiments. It is linked by a salt bridge carrying an aq. potassium chloride (𝐾𝐶𝑙) solution. To evaluate the electrical potential, 𝑍𝑛, as well as 𝐶𝑢 electrodes are dipped in their corresponding electrodes but also attached via a voltmeter. 𝑍𝑛 usually, it works as the anode easily initiate oxidation as well as gains a negative charge. The electrons pass over the salt bridge but are reduced at the 𝐶𝑢 cathode. As a result, the cathode might become positively charged. Such transfer of electrons first from the anode to the cathode causes an electric current to transit in the reverse direction, wherein the voltmeter will determine. The salt bridge now joins the 2 half-cells as well as preserves their electroneutrality. A wire could not be used to interconnect both cells because it'd reacted with ions flowing through one terminal to another. Because of the lower concentration here on the left side as well as the higher concentration on the right side, electrons move from left to right.

Types of Concentration Cells

• Electrode concentration cells − The potential difference within those cells is obtained by dipping two electrodes of distinct concentrations into the identical electrolyte solution. For illustration, a cell of this sort is composed of 2 hydrogen electrodes having distinct gaseous pressures within the identical solution of 𝐻 ions.

• Electrolyte concentration cells − The electrodes in such cells are similar, but they have been dipped in varying concentrations with the relatively similar electrolyte. The propensity of the electrolyte to disperse from such a solution of greater concentration to regions of lower concentration seems to be the origin of electrical energy within the cell. With time, the 2 concentrations start to equalize. As a result, the cell's electromotive force is maximal at first then gradually decreases to 0.

Explain the differences associated with each type of Concentration Cell

Electrolyte concentration Cell	Electrode concentration cell
It is primarily made up of identical electrodes submerged in electrolyte solutions.	These cells are composed of 2 identical solutions. For each half-cell, those liquids have served as such an electrolyte.
The electrolytes within those solutions differ in concentration as well as prefer to flow from either the higher concentration solution into the lower concentration solution.	The concentration of such electrodes varies between half-cells, as the electrodes are formed with the same substance.
$\mathrm{E_{cell}\:=\:\frac{0.0591}{n}\:\log\:\frac{c_{1}}{c_{2}}}$	$\mathrm{E_{cell}\:=0.02955\log\:\frac{P_{i}}{P_{z}}}$

Components of the Concentration Cell

• Salt Bridge − The salt bridge is intended to offer a route for ion exchange while also providing an excellent solution for such dissociation of the 2 half- cells. The electrical cables in it can interact with those ions passing over them. In a certain instance, the lack of such a salt bridge may result in an accumulation of electrons inside the one-half cell as from the arrival of the flow of electrons from another half-cell.

• Electrode − Each Concentration Cell is equipped with 2 electrodes. The 2 electrodes are known as the cathode as well as the anode. The anode starts to lose electrons but is also the region wherein oxidation proceeds, while the cathode prefers to acquire electrons or even seems to be the region wherein reduction takes place.

• Voltmeter − The voltmeter is being used to determine the cell voltage inside a concentration cell. The cell potential is often known as electromotive force (𝑒. 𝑚. 𝑓). This is mostly caused by the movement of electrons. In many of these cases, the voltmeter is situated between such 2 half-cells. The value resulting might be either positive as well as negative, depending on the orientation of the movement of electrons. After that, the voltage is obtained in volts/millivolts.

Conclusion

The reactive component at the anode of the galvanic cell differed from such reactive component at the cathode. Because cell electromotive force varies with concentration, a galvanic cell may be built with similar entities in both half-cells and the concentrations have always been distinct. A concentration cell is a type of cell that is exclusively dependent on the electromotive force produced by a change in concentration. Whereas a galvanic cell, a type of electrochemical cell, generates electricity by using a chemical process to transform chemical energy into electrical energy, and an electrolytic cell cannot. However, an electric current is often used to propagate a chemical reaction, transforming electrical energy into chemical energy.

FAQs

1. Is concentration a factor in electrolytic cells?

Whenever the electrolyte concentration of such acid is larger once at the cathode and then at the anode, the dispersion phenomenon owing to the variation in concentration arises, as well as electrolysis performance increases.

2. What effect does concentration have on electrode potential?

The electrode potential of such a metal fluctuates when the proportion of ions in the solution varies in interaction with the metal. The reduced voltage of such an electrode is directly proportional to the concentration of positively charged ions.

3. How could the electrolyte concentration remain intact throughout electroplating?

The copper ion concentration in the solution is stable. It is due to the electroplating method moving metal from either the cell's anode to its cathode.

4. What's the distinction between a chemical cell and a concentration cell?

The components of two half cells in concentration cells seem to be comparable, however, in chemical cells, the contents might not have been similar. An electrochemical cell is indeed a concentration cell.

5. What would be the significance of a concentration cell?

A pH metre is a sort of concentration cell which can be used to determine the pH, as well as acidity or basicity, of such a solution.