Electrochemistry: Lead Accumulator

The study of generating electricity from the energy released during spontaneous chemical reactions, as well as the application of electrical energy to non-spontaneous chemical changes, is known as electrochemistry. From both a theoretical and a practical sense, this is an essential problem. A variety of metals, sodium hydroxide, chlorine, fluorine, and other chemicals are produced via electrochemical methods.Batteries and fuel cells are widely utilised in a variety of equipment and systems to convert chemical energy to electrical energy. Electrochemical reactions can be both energy efficient and environmentally friendly. As a result, studying electrochemistry is critical for developing new environmentally friendly technology. The transfer of sensory impulses from cells to the brain and vice versa, as well as cell communication, are all known to entail electrochemical processes.As a result, electrochemistry is a very broad and interdisciplinary science.

Electrochemistry

Electrochemistry is a discipline of physical chemistry concerned with the relationship between electrical potential as a quantifiable and quantitative phenomena and recognisable chemical change, with electrical potential as a result of a particular chemical alteration, or vice versa.

An electrochemical reaction occurs when a chemical reaction is affected by a potential difference, as in electrolysis, or when electrical potential comes from a chemical reaction, as in a battery or fuel cell. Electrochemical reactions, unlike chemical reactions, do not transport electrons (and thus ions) directly between molecules, but rather through the aforementioned electrically and ionically conducting circuits. An electrochemical reaction is distinguished from a chemical reaction by this feature.

Lead Accumulator

The lead accumulator is a secondary cell because the electrical energy is not generated inside the cell but rather stored until being supplied by an external source.

It’s a reversible cell since the cell reactions are reversible if the applied external emf is sufficiently larger than the cell’s emf. As a result, total cell reactions are reversed in this cell by exerting external opposition to e.m.f that is bigger than the cell’s e.m.f.

This cell has the ability to store electrical energy from charging or an external source, and it can also supply energy during the discharge process. As a result, the energy is stored in chemical form. As a result, this cell denotes an accumulator, storage cell, or storage battery.

The voltage of the cells is not affected by the size of the electrodes or the size of the cell, but it is affected by the strength of the sulphuric acid solution.

Formation

Lead plates in the form of a negative electrode are used in the lead accumulator. The lead plates, which are brimming with lead oxide, act as positive electrodes. The positive and negative electrodes are arranged in a counterclockwise direction.

This collection of lead plates is immersed in a non-conducting tank constructed of plastic, glass, or ebonite, all of which are non-conductors of electricity and contain 38% hydrogen.

All of the positive plates are linked to one another, and all of the negative plates are linked to one another.

Cell Representation

-Pb(s)| PbSO₄(s)| 38% H₂SO₄(aq)| PbSO₄(s)| PbO₂(s)| Pb(s)+

Working

Cell Discharging: When the cell is turned on, oxidation takes place on the lead plates, followed by reduction using PbO (Lead Oxide). The discharge of the cell is the term for this.

Cell charging: When the emf operating outside is greater than the emf applied to the cell, accurate reverse reactions occur. On positive electrodes, oxidation occurs, while on negative electrodes, reduction occurs. The charging of the cell is the term for this process.

During charging (charging circuit electrode signs):

(+) electrode: PbSO₄(s) + 2H₂O(l) → PbO₂(s) + 4H+(aq) + SO₄^2–(aq) + 2e–

(–) electrode: PbSO₄ (s) + 2e– → Pb(s) + SO₄^2–(aq)

Discharging (electrode signs as for cell):

(+) electrode: PbO₂(s) + 4H+(aq) + SO₄^2–(aq) + 2e– → PbSO₄(s) + 2H₂O(l)

(–) electrode: Pb(s) + SO₄2–(aq) → PbSO₄(s) + 2e–

Now we’ll look at the cell’s overall reaction as it’s being discharged.

PbO₂ + 2H₂SO₄+ Pb → 2PbSO₄ + 2H₂O.

As a result, when sulphuric acid is discharged, it is transformed to H2O (water) and the specific gravity of sulphuric acid is reduced to “1.17.”

Uses of a Lead Accumulator

• As a result of their widespread use in automobiles and other vehicles, lead accumulators are commonly referred to as “car batteries.” Six cells are usually connected in series to provide a voltage of 12V
• In telegraph and telephone offices, lead accumulators are used.
• They have access to radios, electric clocks, and burglar alarms, among other things.
• They are used as a continuous DC voltage source in scientific laboratories

Maintenance of The Lead Accumulator

• It should be kept upright and not slanted.
• When the cell is not in use for an extended period of time, the terminal should be disconnected, the acid from the cells should be removed completely, and the cell should be kept dry.
• To achieve the best cell potential, the concentration of sulphuric acid should be kept constant.
• When the cells are in use, they should not be allowed to run down March. When the voltage is around 1.8 Volt, the EMF of the cell diminishes, and the cells should be recharged.
• The sales should not be overcharged, which means the cell’s emf should not exceed 2.1 Volt.
• By adding distilled water, the acid levels should be adequately maintained.
• For excellent electrical contact, the positive and negative terminals of the lead accumulator should be cleaned from time to time to remove insoluble lead sulphate.
• The cells should be charged on a regular basis and should never be left discharged.

Conclusion

The usage of a lead accumulator is really beneficial. It can be used in a variety of ways. They are utilised as a continuous DC voltage source in laboratories. In telephone and telegraph offices, they are used. They’re found in electric clocks, radios, and burglar alarms, among other things. They’re also used as a source of electricity in the rocket’s early stages.