Daniell cell

Introduction

Daniell cell converts a chemical form of energy into electrical energy. Lets learn more about it.

How does the battery in a mobile phone charge when it is plugged into its charger or how does the cell in a TV remote control function? The study of electrochemistry includes both the use of electricity to conduct non-spontaneous chemical reactions as well as the production of electricity through chemical reactions. Cells are employed to attain the goal. Cells are components that cause chemical reactions that result in electricity or generate electricity.

What are the two types of cells?

• Electrochemical cell

• Electrolytic cell

Electrochemical cell

A system that can generate electrical energy from spontaneous chemical reactions is an electrochemical cell. Redox reactions are the chemical processes that take place throughout this process. Electrons are transferred between chemical species during redox reactions. They are also named Galvanic or voltaic cells. The Daniell cell is an example of an electrochemical cell.

Electrolytic cell

A specific kind of electrochemical cell called an electrolytic cell allows for the utilisation of electrical energy to initiate chemical reactions. In other words, other sources should provide electrical energy. A non-spontaneous reaction can then be started. For the electrolysis of substances, electrolytic cells have been most frequently used.

Electrolytic cells

Difference between electrochemical cells and electrolytic cells

Electrochemical	Electrolytic
Electric energy is created by converting chemical energy.	Chemical energy is created from electric energy.
A redox process produces electrical energy.	Using electricity causes a redox reaction.
The cathode is positive while the anode is negative.	The cathode is negative, while the anode is positive.
Reactions of oxidation and reduction are carried out independently.	In the same container, a redox reaction occurs.
Electrons go through an external circuit from the cathode to the anode.	Electrons go through an external circuit from the anode to the cathode.
A salt bridge is required	A salt bridge is not required

A typical cell structure

A cell has two electrodes: the cathode (+ve electrode) and the anode (-ve terminal). Both electrodes are submerged in the appropriate metal salt solutions. As per the chemical reaction occurring at them, the anode is known as the oxidation half-cell in an electrochemical cell. The cathode is also recognized as the reduced half-cell. A salt bridge that connects the two electrodes, is a U-shaped tube with a gel penetrated with an Electrolyte.

What is a Daniell cell?

An electrochemical cell known as a Daniell cell converts a chemical form of energy into electrical energy. To generate electricity, the cell engages in a variety of chemical reactions. The Zn and Cu electrodes that make up the Daniell cell are used as the anode and cathode, respectively. Both metals are submerged in the corresponding salt solutions.

Zinc (Zn), which serves as the anode in a Daniell Cell, and Copper (Cu), which serves as the cathode, are the two different metals used. Both electrodes continue to be submerged in ion-based chemical solutions. Copper Sulphate and Zinc Sulphate are the appropriate compounds. It is an upgrade on the voltaic cell and generates a differential potential of 1.1 V by utilising the two electrodes made of copper and zinc. The cell, where the electrons travel after being created there at the anode and passed to the cathode, charges the circuit.

Daniell cell chemical reaction

Daniell Cell's internal chemical reaction can be summarised as follows −

$$\mathrm{Zn(s) + Cu^{2+} (aq)\rightarrow Zn^{2+} (aq)+ Cu(s)}$$

• The solid Zn metal undergoes oxidation at the anode, converting it into zinc ions while releasing two electrons.

  $$\mathrm{Zn(s) → Zn^{2+} (aq)+ 2e^- }$$

• These copper ions change into copper metal near the cathode, where they are then further deposited. The formula is

  $$\mathrm{Cu^{2+}+2e^- → Cu(s)}$$

• Through a metal wire connecting the cathode and the anode, the electrons emitted by the Zn at the anode travel there. This specific flow of the electrons moving from the cathode to the anode in the reverse direction results in the production of electricity. To complete the circuit, use the salt bridge.

Daniell cell working

A copper container used in the Daniell Cell houses saturated CuSO₄ and dilute H₂ SO₄ Its functional system consists of

• A solidified zinc rod is still submerged in the solution of zinc sulphate (Zn₂ SO₄ ).

• The CuSO₄ crystals and solution remain kept in contact with one another via a transparent layer that can be seen beneath the copper vessel. The solution is kept saturated as a result.

• The external circuit generates an electric current flow.

• The copper rod gains mass while the Zn rod loses mass.

• While the amount of Copper Sulphate drops, the amount of Zinc Sulphate increases.

• The solutions stay electrically neutral in both containers.

Daniell cell representation

Based on the naturally occurring reaction involving copper ions and zinc, the Daniell Cell is made to generate electrical energy. Zinc metal is oxidised at the negative electrode while copper is reduced at the positive electrode. It is made up of two half-cells connected by a salt bridge. The salt bridge inhibits the mechanical mixing of the solution.

$$\mathrm{Zn | Zn^{2+} (aq) | | Cu^{2+} (aq) | Cu}$$

Where the "| |" stands for the salt bridge, the right side represents the reduction half-cell, and the left side refers to the oxidation half-cell.

Application of Daniell cell

It can be used in

• Battery construction-A battery is a collection of connected Cells.

• Producing electricity-To conserves electric power.

• Inductive telegraphy

Conclusion

An electrolytic cell is a type of electrochemical cell. The electrolytic cell, therefore, has every element that may be found in a typical electrochemical cell. Electron flow across the system is necessary for both electrochemical and electrolytic cells to function. Electrochemical cells, on the other hand, experience spontaneous chemical reactions, whereas electrolytic cells experience non-spontaneous chemical reactions. An electrochemical cell and an electrolytic cell differ in this way.

FAQs

1. Indicate whether Daniell Cells are reversible.

In the Daniell cell, electrons move from the cathode to the anode around the outer circuit. While the positively charged ions are seen to move through the solution from cathode to anode. Daniell's cell is therefore only reversible with minimal current input.

2. A salt bridge is what? State two performs.

The glass tube known as the Salt Bridge is in charge of preserving charge neutrality in the Daniell cell's two compartments.

Functions

• Ion mobility is made possible by the Salt Bridge, which keeps the electric current flowing through the mixture.

• The Salt Bridge contributes to keeping the balance of the charge.

3. Daniell cell's anode is negative, why?

The anode in an electrochemical cell has a negative potential with the solution, but the anode in an electrolytic cell has a positive potential since it is attached to the end of the battery.

4. Why was the cathode in the Daniell Cell positive, specifically?

The removal of the metals from the anode during oxidation causes a buildup of electrons upon that anode, which gradually turns it negative. The elimination of metal ions from the electrolyte results in the consumption of electrons, which turns the cathode positive.

5. What distinguishes the Daniell cell from a voltaic cell?

Depending on the current provided or drawn, a voltaic cell may or not be reversible, whereas the Daniell cell always is.