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APPLICATION OF ELECTROCHEMISTRY

Uses of Electrolysis in

Industries

Extraction of metals

Extract metals from their ores.

Metals that are more reactive than

carbon cannot be extracted through

heating of their metal oxides with

carbon.

Metals that are more reactive need

to be extracted from their moltenores using electrolysis process.

In this process, the molten ore is the

electrolyte and inert electrodes such

as carbon are used as +ve & -veelectrodes.

Purification of metals

Metals that have been extracted

from their ores are normally not pure

& contain impurities which need to

be removed.

In the purification process, the

impure metal is made the anode

while the pure metal is made the

cathode.

The electrolyte is a solution which

contains the metal ions.

During electrolysis, impure metal at

the anode will release electrons &dissolve into the electrolyte as

metals ions.

These metal ions can receive

electrons & form pure metal at thecathode.

The size of impure metal (anode)

become smaller & impurities willsettle at the bottom of the container,

the mass of the impure metal platedecreases.

The size of pure metal (the cathode)

becomes larger due to thedeposition of pure metal, the mass of 

pure metal plate increases.

Electroplating of metals

Many types of metals can be plate

with other metals throughelectrolysis – electroplating.

Aims: - making the metal more

resistant to corrosion, - making thmetal appear more attractive.

Metals such as silver, gold, nickel

copper, chromium, cadmium, zinc @tin are frequently used as plating

metal.

In the electroplating process, platin

metal is used as the anode whilemetal to be plated is used as the

cathode.

The electrolyte used is an aqueou

solution which contains ions of thplating metal.

During electrolysis, plating metal @

the anode releases electrons &dissolves to form metal ions.

Ions of the plating metal then mov

to the cathode, receive electronsthere & form a thin layer of metal o

the cathode.

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BENEFITS OF ELECTROLYSIS IN INDUSTRY

PROCESS BENEFITS

Metal extractionEnables metals that are more reactive than carbon to b

extracted from their ores.

Metal purification Improves the electrical conductivity of substances.

Metal electroplating Improves the resistance of metal against corrosion.

HARMFUL

EFFECTS OF

ELECTROLYSIS

IN INDUSTRY

Electrolyte such as

NaOH solution cancause water

pollution in rivers &oceans & harm

marine life.

Poisonous gases such

as chlorine, Cl2 gascause air pollution.

Nickel salts & chromium

salts, which are used as

electrolytes in thepurification & electroplatingindustries, are poisonous to

human being.

Heavy metals, such as

mercury , used aselectrodes in the

electrolysis of sodium

chloride, NaCl, is toxic &will pollute the

surrounding

environment if it is not

disposed properly.