important of electrolysis

7/29/2019 Important of Electrolysis

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Important Of ElectrolysisElectrolysis is a hugely important process

- it is used industrially in a number of

ways:

(1)The extraction of metals, notably

aluminium, magnesium, and sodium..

(2) The refining of metals, such as copper

and zinc.

(3) Electroplating


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Extraction of Aluminium:

Aluminium is obtained by the electrolytic reduction of its

molten oxide, (alumina). Because alumina has a very high melting point (2045

C), the mineral cryolite is added to lower the meltingpoint in order that the electrolysis may be carried out atabout 950 C.

The electrolytic cell has carbon anodes and a carboncathode (which forms the lining of the tank in which theelectrolysis takes place).

Carbon dioxide is formed at the anodes, and aluminium

at the cathode. It is heavier than the molten alumina/cryolite mixture,

and sinks to the bottom of the cell, where it is tapped off.The procedure is known as the Hall-Hroult process.


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Electrorefining of copper:

When copper is first obtained by reductionof its ores, it is cast as impure slabs oringots, called blister copper.

In the electrorefining process, the blisteringots are used as anodes in anelectrolytic cell, where an acid solution ofcopper (II) sulphate is used as electrolyte.

Initially, the cathodes consist of thin sheetsof pure copper


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During electrolysis, copper passes into solution

from the anodes, (leaving the impurities,

normally containing silver, gold and platinum)as an anode slime, which sinks to the bottom

of the cell. The anode reaction is


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At the cathode, copper (II) ions are

discharged and the pure copper sheet

becomes coated with an increasingly thick

layer of very pure copper:


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Electroplating:

Electroplating consists of depositing a thin

layer of a metal on another, either for

protection or for the sake of appearance.

a brass or nickel object is coated with a

layer of silver by making use of electrolysis

of a silver solution, using the object to be

coated as the cathode:


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Electroplating is used to:

(a) Avoid metal corrosion

(b) Prevent iron from rusting

(c) To make objects to look shiny and better


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Production Of Electrical Energy By

A Simple Cell


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The CELL

A cell is a device that transforms chemical

energy into electrical energy

It consists a piece carbon (C) and a piece

zinc (Zn) suspended in a jar that contains

a solution water and sulfuric acid

A cell is a device in which chemical energy

is converted to electrical energy.


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The current flow is the movement of

electrons from the negative electrode the

cell (zinc) and to the positive electrode

(carbon).

This causes fewer electrons in the zinc

and an excess electrons in the carbon.

The hydrogen ions (H2) from the sulfuric

acid being attracted to the carbon

electrode.


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The zinc electrode has a positive chargebecause it has lost electrons to the carbon

electrode. This positive charge attracts the negative

ions (S04) from the sulfuric acid.

The negative ions combine with the zinc toform zinc sulfate.

This action causes the zinc electrode to beeaten away. Zinc sulfate is a grayish-whitesubstance that is sometimes seen on thebattery post an automobile battery.

important of electrolysis

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