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Applications of electrochemistry

Electrochemistry has a number of different uses, particularly in industry. We are going to look at a few examples.

Electroplating

Electroplating is the process of using electrical current to coat an electrically conductive object with a thin layer of metal. Mostly, this application is used to deposit a layer of metal that has some desired property (e.g. abrasion and wear resistance, corrosion protection, improvement of aesthetic qualities etc.) onto a surface that doesn't have that property. Electro-refining (also sometimes called electrowinning is electroplating on a large scale. Electrochemical reactions are used to deposit pure metals from their ores. One example is the electrorefining of copper.

Copper plays a major role in the electrical reticulation industry as it is very conductive and is used in electric cables. One of the problems though is that copper must be pure if it is to be an effective current carrier. One of the methods used to purify copper, is electrowinning. The copper electrowinning process is as follows:

  1. Bars of crude (impure) copper containing other metallic impurities is placed on the anodes .
  2. The cathodes are made up of pure copper with few impurities.
  3. The electrolyte is a solution of aqueous C u S O 4 and H 2 S O 4 .
  4. When current passes through the cell, electrolysis takes place. The impure copper anode dissolves to form Cu 2 + ions in solution. These positive ions are attracted to the negative cathode, where reduction takes place to produce pure copper metal. The reactions that take place are as follows: At the anode :
    C u ( s ) C u 2 + ( a q ) + 2 e -
    At the cathode :
    C u + 2 ( a q ) + 2 e - C u ( s ) ( > 99 % purity )
  5. The other metal impurities (Zn, Au, Ag, Fe and Pb) do not dissolve and form a solid sludge at the bottom of the tank orremain in solution in the electrolyte.
A simplified diagram to illustrate what happens during the electrowinning of copper

The production of chlorine

Electrolysis can also be used to produce chlorine gas from brine/seawater (NaCl). This is sometimes referred to as the 'Chlor-alkali' process. The reactions that take place are as follows:

At the anode the reaction is:

2 C l - C l 2 ( g ) + 2 e -

whereas at the cathode , the following happens:

2 N a + + 2 H 2 O + 2 e - 2 N a + + 2 O H - + H 2

The overall reaction is:

2 N a + + 2 H 2 O + 2 C l - 2 N a + + 2 O H - + H 2 + C l 2
The electrolysis of sodium chloride

Chlorine is a very important chemical. It is used as a bleaching agent, a disinfectant, in solvents, pharmaceuticals, dyes and even plastics such as polyvinlychloride (PVC).

Extraction of aluminium

Aluminum metal is a commonly used metal in industry where its properties of being both light and strong can be utilized. It is also used in the manufacture of products such as aeroplanes and motor cars. The metal is present in deposits of bauxite which is a mixture of silicas, iron oxides and hydrated alumina ( A l 2 O 3 x H 2 O ).

Electrolysis can be used to extract aluminum from bauxite. The process described below produces 99 % pure aluminum:

  1. Aluminum is melted along with cryolite ( N a 3 A l F 6 ) which acts as the electrolyte. Cryolite helps to lower the melting point and dissolve the ore.
  2. The anode carbon rods provide sites for the oxidation of O 2 - and F - ions. Oxygen and flourine gas are given off at the anodes and also lead to anode consumption.
  3. At the cathode cell lining, the A l 3 + ions are reduced and metal aluminum deposits on the lining.
  4. The A l F 6 3 - electrolyte is stable and remains in its molten state.

Questions & Answers

what is the difference between momentum and a change in momentum?
Chavonne Reply
How to name a branched molecule from right or left?
Vadin Reply
What's Free Fall
Senzo Reply
Free Fall means there is no acting force on that object.
Dingaletu
only gravitational force
Dingaletu
no external force acting on an object
Sphiwe
by only force of gravite
Sello
but gravitational force
Sphiwe
true
Lucky
Do polymers form restrictedly only if compound is saturated, only?
milani Reply
what is a free fall?
Beyanca Reply
is when The Only Force acting On an Object is Gravitational Force
Madman
Thats right
Beyanca
then Why ask when you Know the answer?
Madman
She's just helping those who forgot it...bro
Thato
guys I need help on Getting ready for a last minute test
Kenelioe Reply
what help you need
Neil
we'll I'm in grade 12 so we doing this topic about upac thing
Kenelioe
on What?
Madman
the organic molecule section
Kenelioe
IUPAC NAMING WHICH FUNCTIONAL GROUP YOU CANNOT NAME?SO I COULD HELP YOU
Madman
ester
Sboniso
you should also look at structural isomers. Its crucial that they might add that one. also try and write down the structural formula of all the given compounds on the table
milani
hi guys i can explain everything in terms of physics and chemistry
Neil Reply
😂😂😂😂😂
Madman
yes
Lucky
yea
Kenelioe
guys 2mrrow I'm writing a test in chemistry I need help
Kenelioe
Hi guys. Can anyone please tell me what a functional group is?
Samukelo
a functional group depends on how many bonds there are between carbon atoms, if there are single bonds all the way it's an alkane, if there is a presence of at least one double bond it's a Alkene and if there's at least one triple bond it's an alkyne.
Olive
which quantity is measured in Watt?
Saara Reply
work
Absai
explain for me absai
Sboniso
is Power Not Work work is Measured In Joules it has Energy
Madman
thanks
Saara
Pleasure
Madman
what is galvanic cell ?
Oratile Reply
is an electrochemical cell that derives electrical energy from spontaneous redox reactions taking place within the cell.
Hope
how to understand alkane names
Sboniso Reply
suffix Ane in the IUPAC NAMING
Madman
elaborate a little more plz
Kenelioe
Alkanes are Saturated Meaning they don't have Multiple Bonds between Carbon Atoms and When you are Naming THEM THEY MUST END WITH (-ANE ) GET ME?
Madman
What are hydrocarbons
Phelo Reply
are organic Compounds with only Carbon and Hydrogen Atoms
Madman
whats the difference between aldehydes and ketones
Angel Reply
definition of chain parent
Lea Reply
what is wave?
Agness Reply
when butane burns in an excess of oxygen ,the products are
Slay
CO2 and H2O
GARY
Carbon dioxide and Water...
Thato
what is hydrocarbon
Ntswaki Reply
Hydrocarbon is a compostion of mainy carbon and hydrogen
Tsion
hydrocarbon compound made up of carbon and hydrogen only
Thembelani

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Source:  OpenStax, Siyavula textbooks: grade 12 physical science. OpenStax CNX. Aug 03, 2011 Download for free at http://cnx.org/content/col11244/1.2
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