Week 10-11 Module

TECHNOLOGICAL UNIVERSITY OF THE PHILIPPINES VISAYAS
Capt. Sabi St., City of Talisay, Negros Occidental
College of Engineering Technology

Office of the Program Coordinator
LECTURE MODULE
CHEM 134:
General Chemistry 2
DEPARTMENT: CHEMICAL ENGINEERING TECHNOLOGY
COMPILED BY:
FRITZIE B. ASUNCION, MT GREDA G. BALACUIT, RCh
MA. AGNES G. DINGCONG ALPHA J. HERMOSURA, RChE
EDELYN G. LOBATON, RChE
2021
This module is a property of Technological University of the Philippines Visayas and intended
for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.
VISION
The Technological University of the Philippines shall be the premier state university
with recognized excellence in engineering and technology at par with leading universities in
the ASEAN region.
MISSION
The University shall provide higher and advanced vocational, technical, industrial,
technological and professional education and training in industries and technology, and in
practical arts leading to certificates, diplomas and degrees.
It shall provide progressive leadership in applied research, developmental studies in
technical, industrial, and technological fields and production using indigenous materials; effect
technology transfer in the countryside; and assist in the development of small-and-medium
scale industries in identified growth center. (Reference: P.D. No. 1518, Section 2)
QUALITY POLICY
The Technological University of the Philippines shall commit to provide quality higher
and advanced technological education; conduct relevant research and extension projects;
continually improve its value to customers through enhancement of personnel competence and
effective quality management system compliant to statutory and regulatory requirements; and
adhere to its core values.
CORE VALUES
T - Transparent and participatory governance

U - Unity in the pursuit of TUP mission, goals, and objectives
P - Professionalism in the discharge of quality service
I - Integrity and commitment to maintain the good name of the University
A - Accountability for individual and organizational quality performance
N - Nationalism through tangible contribution to the rapid economic growth of the
country
S - Shared responsibility, hard work, and resourcefulness in compliance to the mandates
of the university
TABLE OF CONTENTS
Page Numbers
TUP Vision, Mission, Quality Policy, and Core Values…………………………. ii
Table of Contents……………………………………………………………..……. iv
Course Description ..……………………………………………………….. iv
Learning Outcomes………………………………………………………… iv
General Guidelines/Class Rules…………………………………………… iv
Grading System ………………………………………………………….... v
Learning Guide (Week No. 10-11) …………………………………………..
Topic/s …………………………………………………………….. 1
Expected Competencies …………………………………………... 1
Content/Technical Information …………………………………… 1
Progress Check …………………………………………………… 16
References ………………………………………………………… 18
Learning Guide (Week No. 12) ……………………………………………..
Topic/s …………………………………………………………….. 19
Progress Check …………………………………………………… 36
References ………………………………………………………… 39
Learning Guide (Week No. 13) ……………………………………………..
Topic/s …………………………………………………………….. 40
Progress Check …………………………………………………… 49
References ………………………………………………………… 49
COURSE DESCRIPTION
This is the second part of a two-semester course on the fundamental concepts

of acids, bases and salts. It also deals with the components of a solution; the different
methods of expressing concentration of solutions; standardization of solutions;
volumetric analysis; colligative properties of solutions; chemical equilibrium; acid-
base equilibria; electrochemistry; electrochemical cells and the introduction to Organic
Chemistry.
LEARNING OUTCOMES
LO1: Perform general chemistry laboratory experiments following specified

procedures either individually or as a member of a team; demonstrate basic chemistry
laboratory techniques;
LO2: Correctly use common laboratory glassware and equipment to make

measurements and perform experiments;
LO3: Gather, record, organize, and interpret data collected from experiments and use the
scientific method to derive conclusions appropriate to the scope and quality of data;
LO4: Recognize the limitations of experimental and observational methods; carry out
laboratory measurements and calculations using the correct significant figures.
GENERAL GUIDELINES/CLASS RULES
Course Requirements:
Students should:
1. Answer all questions found in the Progress Check section of this module.
2. Communicate with the assigned Professor/Instructor regarding the output
relative to the Progress Check or additional activities assigned.
3. Outputs should observe the following:
a) Use short-sized bond paper.
b) Answers must be legibly hand-written.
4. Submit all activities or requirement on or before due dates.
5. Forward assigned tasks/ activities/ assessments thru Messenger Group Chat,
Google Classroom, NEOLMS, e-mail..etc…as assigned by your instructor
6. Communicate and coordinate with the assigned Professor/Instructor below
regarding any concern, or question about the subject:
Name of Professor/Instructor official e-mail add

Fritzie B. Asuncion : fritzie_asuncion@tup.edu.ph
Alpha J. Hermosura : alpha_hermosura@tup.edu.ph
Jant Erbert S. Garboso : jant_garboso@tup.edu.ph
Lowela C. Villarias : lowela_villarias@tup.edu.ph
Junella Trixia C. Porol : junella_porol@tup.edu.ph
Edelyn G. Lobaton : edelyn_lobaton@tup.edu.ph
Charity Huna B. Fabon : charityhuna_fabon@tup.edu.ph
Leopoldo C. Radan, Jr. : leopoldo_radan@tup.edu.ph
Mark Lester G. Viendo : mark_viendo@tup.edu.ph
***Always indicate your full name and course/year/section when you make inquiries.
Note: For CLASS MAYORS
1. Please provide the instructor via email a word file document containing the
following contact information of the entire class:
a. Full Name
b. Mobile or landline numbers (indicate network providers)
c. Email address
d. Facebook Messenger ID
2. Create a Group Chat on Messenger and add your classmates.
Grading System
The student will be graded according to the following:
Average of examinations - 40%

Average of weekly assessment - 60%
Pre-lim Grade : [(Prelim exam x 0.40) + (Assessment: 50% Quizzes+ 50%

Laboratory Worksheet Rating) x 0.60] x 0.30
Mid term Grade : [(Midterm exam x 0.40) + (Assessment: 50% Quizzes+ 50%
Endterm Grade : [Endterm exam x 0.40) + (Assessment: 50% Quizzes+ 50%

Final Grade : Prelim Grade + Midterm Grade+ Endterm Grade
The passing grade for this course is 5.0.
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LEARNING GUIDE
Week No.: _10-11
TOPIC/S
Introduction to Electrochemistry
Principles of Electrolysis
Application of Electrolysis
Electrochemical Cell
History of Battery
Essential Parts of Battery
Types of Batteries
Classification of Batteries
Application of Batteries and its Uses
Different Battery Sizes
EXPECTED COMPETENCIES
At the end of the lesson, you must have:
1. defined electrochemistry;
2. explained the principle of electrochemistry;
3. distinguished between electrolytes from non-electrolytes;
4. explained the mechanism of ionization and dissociation;
5. defined electrolysis;
6. identified and labeled the components of an electrolytic cell;
7. explained the process and reactions involved in electrolysis;
8. related electrolysis to its various industrial applications;
9. cited daily life examples of electrolysis;
10. identified and labeled the components of electrochemical cells;
11. discussed the operation and chemical reactions involved in an
electrochemical cell;
12. defined service life of a battery;
13. outlined the history of battery;
14. classified batteries;
15. explained the different characteristics and applications of batteries;
16. written down the different reactions during battery operation;
17. listed other special types of batteries;
18. identified different battery sizes, their uses and
19. cited and identified different ways on how to handle and dispose of batteries
properly.
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CONTENT/TECHNICAL INFORMATION
Introduction
Figure 10.1
A variety of batteries of different sizes, composition, and voltages
We are surrounded by
an amazing array of
portable electronic
gadgets, including
cell phones, portable
music players, laptop
computers, and
gaming devices. In
the absence of
batteries, however,
our electronic
gadgetry would be
nothing more than
extra weight. Thus, a
variety of
(Source: https://www.webstaurantstore.com/guide/923/batteries-buying-guide.html) batteries of
different sizes,
compositions, and voltages have been developed, some of which are shown in Figure 10.1.
Considerable research is in progress to develop new batteries with more power, faster
recharging ability, lighter weight, or cheaper price. At the heart of such development are the
oxidation-reduction reactions that power batteries. As we discussed in the previous term,
oxidation is the loss of electrons in a chemical reaction, and reduction is the gain of electrons.
Thus, oxidation-reduction (redox) reactions occur when electrons are transferred from an atom
that is oxidized to an atom that is reduced. Redox reactions are involved not only in the
operation of batteries but also in a wide variety of important natural processes, including the
rusting of iron, the browning of foods, and the respiration of animals.
Electrochemistry defined
Electrochemistry is best defined as the study of the interchange of chemical and electrical
energy. It deals directly with electrons and their movement. It is primarily concerned with two
processes that involve oxidation-reduction reactions: the generation of an electric current from
a chemical reaction which takes place in a battery and the opposite process that uses current to
produce chemical change known as electrolysis.
Electrochemistry is an important component of General Chemistry since it is one of the

most important interfaces between chemistry and everyday life. Every time you start your car,
turn on your calculator, look at your digital watch or use your cell phones, you are depending
on electrochemical reactions.
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Recall/Review:
Oxidation-Reduction Reaction
Any electrochemical process involves oxidation-reduction reaction in which electrons are

transferred from atom that losses electron to the atom that gains electron. Oxidation involves
a loss of electron that results to an increase in the oxidation number while reduction involves
gain of electron that results to a decrease in the oxidation number. However, electrons can’t
simply be lost, they have to go somewhere, the electrons “lost” in oxidation must be gained in
the simultaneous reduction reaction of another atom.
Example of Oxidation-Reduction or Redox reaction:
A clean copper wire placed in a colorless solution of silver nitrate

will undergo a redox reaction, Ag+ ions will be reduced forming
silver metal that will deposit on the copper wire. The colorless
solution will turn to blue as the copper metal will be reduced to form
Cu+2 ions.
Oxidation : Cu0(s) ➔ Cu+2(aq) + 2e-
Reduction : Ag+(aq) + 1e- ➔ Ag0(s)
Electrolytes and Non-electrolytes
An essential component of an electrochemical cell is the electrolyte. Electrolyte is

defined as a substance whose solution conducts electricity, while a substance whose solution
does not conduct electricity is a non-electrolyte.
One particularly useful property for characterizing a solution was first identified by
Arrhenius. According to Arrhenius the ability of solutions to conduct electrical current
depends directly on the number of ions present in the solution.
Mechanisms Involved in the Formation of Ions
1. Dissociation is the separation of ions from electrovalent compound by the action of a

solvent.
Suppose a few crystals sodium chloride is dropped into a beaker of water, the water
dipoles will exert an attractive force on the ions forming the crystals. The negative
oxygen and several water dipoles will exert attractive force on a positive sodium ion.
Likewise, the positive hydrogen end of the other water dipoles exerts an attractive
force on the negative chloride ion. This weakens the bond between the sodium and
chloride ions. The ions then turn away from the crystal lattice to diffuse throughout
the solution and are loosely bonded to the water molecules.
In this way, a salt crystal is gradually dissolved and the ions spread throughout the
solution. This may be represented by an ionic equation below.
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H2O
NaCl(s) ➔ Na+(aq) + Cl-(aq)
2. Ionization is the formation of ions from polar covalent compound by the action of a
solvent.
When HCl is dissolved in water, the same phenomenon as that of NaCl occurs. The
polar water molecules break the covalent bond and chlorine keeps the shared electrons
forming hydrogen ion (H+) and chloride ion (Cl-) in solution as shown by the equation
below.
H2O
HCl(concd) ➔ H+(aq) + Cl-(aq)
Classification of Electrolytes
The classification of electrolytes is based on experimental observations. Solutions are

tested by the use of a lamp connected to a pair of electrode which can be dipped into the test
solutions. A battery or some other power supply serves as the source of current. From the test,
solutions are classified as:
1. Strong electrolytes are good conductors of electricity. They cause the lamp to glow
brightly and the ammeter records a large amount of current. They are 100% ionized
or dissociated in solutions.
Examples:
soluble salts
strong acids
strong base
2. Weak electrolytes are substances that produce relatively few ions when dissolved in
water. These are poor conductors of electricity. The lamp gives a dim light and the
ammeter records a very small current. They are slightly ionized or dissociated in
solution.
Examples:
weak acids
weak bases
Non-electrolytes
Compound whose solutions will not conduct current is called non-electrolyte. In general,
compounds other than acids, bases, and salts are classified as non-electrolytes. In a solution of
non-electrolyte molecules retain their identity. For example, when sugar is dissolved in water,
the sugar exist in the solution as solvated or hydrated molecules surrounded by a cluster of
water but they are electrically neutral hence there is no electrical conductivity.
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Colligative Properties of Solutions of Electrolyte and Non-electrolyte
Colligative properties are dependent on the number of particles present in the solution
but not on the nature of the solution.
1. Effect in freezing point of pure solvents
One mole of any non-electrolyte dissolved in 1kg solvent produces the same
lowering of freezing point as does one mole of any other non-electrolyte because 1
mole of any non-electrolyte contains 6.023x1023 molecules. However, the lowering
of the freezing point produced by 1 mole of a strong electrolyte is much greater than
that of one mole of a non-electrolyte because the electrolyte ionizes when it dissolves.
2. Effect in the boiling point of pure solvents
Similarly a solution of 1 mole of electrolyte will raise the boiling point of its
solvents nearly 2 or 3 times more than the same amount of non-electrolyte solution.
ELECTROLYSIS
The process whereby a current of electricity is used to bring about oxidation-reduction

reactions that do not take place simultaneously is called “electrolysis”.
Nature of Electrolysis
Electrolysis is carried out in an electrolytic cell which consists of two electrodes in a

molten salt or solution. The cell is driven by a battery or some other source of direct electrical
current. The electrode from which electrons are withdrawn (oxidation) is labeled as positive.
The one receiving the electrons (reduction) is labeled as negative. Just as in a battery, the
electrode at which reduction occurs is called the cathode and the electrode at which oxidation
occurs is called the anode.
Notice that the sign convention for the electrodes in an electrolytic cell is just the opposite
of that of a battery. The cathode in the electrolytic cell is negative because electrons are being
forced into it by the external voltage source. The anode is positive because electrons are being
withdrawn by the external source.
A. Components of Electrolytic Cell
1. electrodes - a pair of conducting metal

a. anode - positive electrode
b. cathode – negative electrode
2. electrolytic solution (electrolyte) – supplies the positive and negative ions.
3. container
4. power source (battery or other direct current source)
5. connecting wires
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B. The Basic Set-up of an Electrolytic Cell
(Source: https://www.savemyexams.co.uk/notes/igcse-
chemistry-cie-new/5-electricity-chemistry/5-1-
electrochemistry/5-1-1-electrolysis/)
C. Operation of Electrolytic Cell
During operation, the battery creates an electric field which pushes the electrons
towards the cathode. Electrons are therefore crowded on the cathode and drained away
from the anode. To complete the electric circuit, electrons at the cathode must be used
up while electrons must be formed at the anode. To achieve this, chemical changes
must occur on both electrodes. At the cathode, reduction occurs while oxidation occurs
at the anode. The reactions are:
At the anode: X- ➔ X + 1e- (oxidation)
At the cathode: M+ + 1e- ➔ M (reduction)
where:
M+ = positive ion
X- = negative ion from electrolyte
In order that the electrolysis process is maintained, positive ions must keep moving
toward the cathode to accept the electrons and be reduced. Simultaneously negative
ions must migrate toward the anode to give up excess electrons and be oxidized.
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D. Applications of Electrolysis
1. Electrolysis of Water
The cell contains two platinum electrodes which are immersed in water
containing a small amount of electrolyte such as sulfuric acid. The passage of
current from the power source causes the following reduction-oxidation reactions
to take place:
Cathode reaction: H+ + 1e- ➔ H0

H0 + H0 ➔ H2
Anode reaction: 2 H2O ➔ O2(g) + 4 H+ + 4e-
Over-all cell reaction: 2 H2O ➔ O2(g) + 2 H2(g)
2. Electroplating
Electroplating is a process in which a coating of metal is added to a conductor with

the help of electric current. The process which is used in electroplating is
electrodeposition. In electroplating, the object to be plated is made the cathode. The
anode is the metal which is to coat the object. The electrolyte is the solution of the
metal which is the anode.
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10 Daily Life Examples of Electroplating
Almost every other thing surrounding us consists of metals; the amount of metal in some
things is less whereas, in some it is high. The computers and mobile phones which we use
on a daily basis are manufactured with different types of metals ranging from expensive
to the cheapest ones. Picturing the world without metals is a bit difficult. Some metals
are considered far more attractive and valuable than others; gold and silver are the oldest
examples of the same. As such metals are very expensive, one might have to think twice
before buying them. Electroplating is a procedure whereby a thin layer of gold and silver
is put on a cheaper metal, and the final product is available at an affordable cost.
Here are the daily life examples of electroplating:
1. Aesthetics
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Although gold and silver are one of the most expensive metals and a
person has to plan his budget accordingly to buy gold jewelry.
Therefore, electroplating is an alternative as well as a cost-effective
method to purchase jewelry. A thin layer of precious metal is often
coated on jewelry to make it more lustrous and attractive to potential
buyers.
2. Protective Barriers
The long life of steel and iron is only due to electroplating. They are
plated with other metals like nickel or chromium which prevent the base
metal from getting corroded. Hence, electroplating acts as a protective
barrier for the metals. It covers the surface of the metal and protects
them from different atmospheric conditions. Plated parts last longer and
can tolerate extreme conditions.
3. Prevent Friction
buyers.
Nickel plating is done on a metal surface to reduce friction in

materials like electric conductors. It reduces the chances of early wear
and tear of the metal.
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4. Conduction of Electricity
Gold and silver are good conductors of electricity, but they are a bit
costly. So, metals are plated with silver and gold to increase their
conductivity and decrease cost. Cell phones, computers, and other
electronic devices use electroplating techniques in their circuits.
Interestingly, the medals meant to be awarded in the 2020 Tokyo
Olympics and Paralympic Games are manufactured from metals
extracted from mobile phones and other recycled waste items.
5. Prevent Tarnishing
Many household items including silverware retain their elegance and

hold their value for a period of time. Electroplating protects metals
against premature tarnishing and also decreases the likelihood of
scratching.
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6. Increasing Thickness
Electroplating is used to improve the overall quality and longevity of a

substrate. For instance, palladium plating which is done over other
metals increases the thickness as well as durability of the metal. It is also
used to make the brittle metal hard and strong.
.
7. Protection from Radiations
Electroplating is also used to plate desired characteristics on the metals

which lack those characteristics. This helps in protecting the metals
from radiations. Gold’s reflective properties make it ideal for
use in components such as semiconductor parts including reflector
rings and reflector arrays. Gold reflects UV radiation below 0.35
µm. It also reflects infrared radiations with wavelengths above
0.7 µm, which helps to keep electronics cool. These reflective
properties have made gold plating an integral part of spacecraft and
satellite design.
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8. Commercial applications
Electroplating is used in various commercial appliances. Nickle is used

in decorative items, cars, and machinery parts. Chromium is also used
in rims of wheels and zinc is also plated on various machinery parts.
.
9. Smoothness
Every metal item we purchase, for example, utensils, are very smooth
and lustrous. Copper plating is done to provide extra smoothness to the
metal surface. It provides enhanced surface finishing to the metal.
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10. Aerospace and Aviation
Have you ever wonder how astronauts travel to space where there is a
high level of solar heat? Gold plating is done on astronaut’s helmet
for protection from dangerous effects of solar radiation. Also, many
satellites carry gold coated mylar sheet to protect them from solar heat.
4. Anodizing
Anodizing is an electrochemical process that converts the metal surface into

a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminum is ideally
suited to anodizing, although other non-ferrous metals, such as magnesium and
titanium, also can be anodized. Aluminum is made the anode of an electrolytic cell.
The electrolyte used is usually a dilute solution of sulfuric acid as shown in the
figure below. The oxygen generated at the anode by the passage of current through
the electrolyte reacts with the aluminum to produce a film of aluminum oxide on it
which acts as a protective coating for aluminum.
Anodizing Diagram
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The temperature of the solution is controlled to give the desired properties, e.g. at 20oC
a sulfuric acid anodizing solution will give a soft, transparent clear, easily dyed coating whereas
at 5oC a hard, dense, dull grey coating is produced (hard anodizing).
A DC (direct current) electric current is passed between the aluminum that is made the
anode (positive terminal), the electrolyte and a cathode (often lead).
When the current is applied, the water in the

electrolyte breaks down and oxygen is deposited at
the anode. This oxygen combines with the aluminum
to form oxide and thus builds on the oxide film
always present on the surface.
The acid in the electrolyte tries to dissolve this

oxide and produces a porous oxide film on the
aluminum surface. Coating thickness up to 25
microns is recommended for external use. The oxide
grains are hexagonal in shape and each grain contains
a hexagonal hole within it.
Once the required thickness of anodic film is

obtained, the aluminum is removed from the
electrolyte and rinsed thoroughly to remove the acids
from the pores in the film. The anodic film produced
from sulfuric-based electrolytes is now ready for
coloring, if required.
Examples anodized products:
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5. Purification of Blister Copper
Blister copper consists of an impure form of copper produced by blowing air

through molten copper matte. During the conversion process, sulfur, iron and
other impurities are oxidized. The copper content s normally about 98 % by weight.
It contains impurities mainly Fe, As, Zn, Pb, Ag and Au. These impurities
adversely affect the electrical as well as the mechanical properties of copper. The
copper so obtained is called “blister copper” because, as it solidifies, SO2 hidden in it
escapes out producing blister on its surface as shown on the picture below:
Blister Copper
Blister copper is refined by electrolysis. Thin sheets of pure copper serve as the cathode
and slabs of impure copper serve as the anode as shown in the figure below. The
electrolyte is a solution of copper sulfate. During electrolysis, the copper ion moves
toward the cathode where they plate out as pure copper. The impure copper anode
supplies copper ions for the solution.
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Reactions: Cu++ + 2e- ➔ Cu0 (cathode)
Cu0 ➔ Cu++ + 2e- (anode)
As the process continues the anode becomes thinner while the cathode becomes
thicker. Pure copper metal is deposited on it. The impurities drop to the bottom of
the cell known as the anode mud or sludge. The electrically refined copper is
99.99% pure.
6. Extraction of Metals
Aluminum is one of the metals extracted from its ore by electrolysis. It is a very
useful metal but expensive to produce. Aluminum is theoretically a very reactive metal,
so, because its position in the reactivity series of metals, aluminum cannot be extracted
using carbon because it is above carbon in the reactivity series i.e. more reactive than
carbon in the series.
o Carbon is not reactive enough to displace aluminum from its compounds such
as aluminum oxide.
So, if aluminum is too reactive to be obtained by carbon reduction of its oxide another
method must be employed which is called electrolysis.
Aluminum is obtained from mining the mineral bauxite which is mainly aluminum
oxide (Al2O3) and bauxite must be purified prior to electrolysis, adding to the
manufacturing costs.
The purified bauxite ore of aluminum oxide is continuously fed in. The
mineral cryolite is added to lower the melting point and dissolve the ore. So, the
electrolyte is a mixture of molten aluminum oxide and cryolite minerals. The cell
contains molten aluminum ore or Al2O3. The electrodes are made of carbon.
o The addition of cryolite brings the melting point of aluminum oxide down to
~900oC.
o The melting point of aluminum oxide is over 2000oC and it would require a lot
of extra energy to keep purified bauxite ore molten for the electrolysis to take
place - remember the ions (Al3+ and O2–) must be free to move to electrodes for
the electrolysis to work.
During the process, the reactions are:
Cathode: Al 3+ + 3e- ➔ Al0

Anode: O 2- ➔ O0 + 2e-
O0 + O0 ➔ O2
C + O2 ➔ CO2(g)
The carbon anodes are slowly consumed during the process. So, the carbon–graphite
electrode is regularly replaced.
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The figure below shows the basic design of the industrial electrolysis cell used in the
extraction of aluminum from molten purified aluminum oxide extracted from bauxite ore:
7. Manufacture of other Elements and Compounds
Chlorine gas, hydrogen gas and sodium hydroxide are produced by the
electrolysis of aqueous sodium chloride. Sodium, like many of the most reactive
metals, can be extracted by electrolysis of its molten chloride.
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The three products from the electrolysis of sodium chloride solution are all of industrial
significance: hydrogen, chlorine and sodium hydroxide.
Overall equation for the electrolysis of brine:
2NaCl(aq) + 2H2O(l) ==> H2(g) + Cl2(g) + 2NaOH(aq)
ELECTROCHEMICAL CELL
Introduction
One of the two electrochemical processes is the generation of electric current from a
chemical reaction, the same process occurs in a battery. At the heart of any battery is a chemical
reaction that releases energy.
Electrical energy arises from moving a charge. To power any conventional electrical
device, we need to move electrons through a wire. So, if a chemical reaction is going to
produce useful electrical energy, it will need to function as a course of moving electrons. These
electrons must move through closed cycle. Electrons released at one terminal of the battery
must be recaptured at the opposite terminal to complete the circuit.
An oxidation-reduction reaction involves the transfer of electrons from one atom to

another. A battery is a cleverly engineered application of an oxidation reduction reaction. It
is a device in which chemical energy is changed to electrical energy, hence it can be used as a
portable power source. Batteries provide mobility and reliability, less expensive and simpler
than other power supplies.
The battery is one of the most important man-made inventions all throughout history.
Today, it is generally used as a portable source of power, but in the past, batteries were our only
source of electricity. Without its conception, modern comforts such as computers, vehicles and
communication devices may not have been possible.
The Earliest Battery
Before Benjamin Franklin discovered electricity in the 1740s, the concept of batteries
may have already been in existence, since as early as 2,000 years ago. In 1983, a group of
archaeologists have discovered a collection of terracotta jars in Khujut Rabu, a village near
Baghdad. The jars contained sheets of copper rolled up with an iron rod. Wilhelm König, one
of the German archaeologists, discussed the possibility of this copper and iron combination as
a form of galvanic cells used as a battery. When mixed with an acidic liquid, copper and iron
can produce a chemical reaction that results in electricity. It is thought that this earliest form of
battery may have been used to electroplate gold into the artifacts of the Parthian Civilization.
The Parthian Dynasty existed between 250 BCE to 250 CE .
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1786: Frog Legs and Electricity
Luigi Galvani, an Italian physicist, discovered a hint that paved the way to the idea of
the battery. Galvani was dissecting a frog attached to a brass hook with an iron scalpel, and as
he touched the frog’s leg, the leg twitched. The physicist believed that this was due to “animal
electricity” wherein the energy that sparked the movement came from the leg itself. This was
greatly opposed by Alessandro Volta, who believed that the phenomenon was caused by the
two dissimilar metals and a humid conductor. Volta verified this concept through an
experiment, which he published in 1791.
1800: The Birth of The Voltaic Pile
Volta took his research further by making the first wet cell battery. Putting together
layers of copper and zinc divided by layers of cardboard or cloth soaked in brine, Volta came
up with what is now known as the voltaic pile. The Voltaic Pile is the first true battery,
producing a stable and consistent current. But despite of being capable of delivering consistent
currents, the Voltaic Pile cannot produce electricity for a long time. Volta’s batteries only offer
a short battery life, which is an hour’s worth at maximum. One of its flaws
involves electrolyte leaks which cause short-circuits. Another problem is the formation of
hydrogen bubbles on the copper, increasing the internal resistance of the battery.
1820: The Daniell Cell Battery
British chemist John Frederic Daniell paved the way to overcoming the Voltaic Pile’s
restriction by inventing the Daniell Cell. Hydrogen bubbles were eliminated by using a second
electrolyte solution produced by the first conductor. The Daniell Cell made use of copper
sulfate immersed in an unglazed earthenware vessel filled with a zinc electrode and sulfuric
acid. Since it was made out of porous material, the earthenware vessel allowed ions to pass
through but prevented the solutions from mixing. The Daniell Cell was also the first battery to
incorporate mercury, used to reduce corrosion. This battery type produced 1.1 volts and was
initially used to power communication devices.
1838: The Porous Pot Cell
A Liverpool-based instrument maker, John Dancer, used the design of the Daniell Cell.
This battery was composed of a central zinc anode soaked into an earthenware vessel
containing a solution of zinc sulfate. The porous earthenware pot is immersed in a solution of
copper sulfate contained inside a copper can. The copper can acts as the cell’s cathode. Ions
pass through the porous barrier but the solutions are kept from mixing together.
1859: The Arrival of Lead Acid Batteries
All batteries previously invented were primary cells, and so they permanently drained
after all their chemical reactions were spent. Gaston Planté solved this problem by creating the
first battery that could be recharged: the Lead-Acid Battery. By passing a charging and
discharging current in the cell, the battery can supply energy for a longer time. A scientist
20
named Camille Alphonse Faure enhanced the lead-acid battery. Faure designed a cell
consisting of a lead grid lattice in which the lead oxide paste was pressed. Layers of these plate
combinations were stacked for greater performance. The first model for a lead-acid battery
was composed of two lead sheets divided by rubber strips forming a spiral. Lead-acid batteries
were first used to power lights for train carriages.
1866: The Leclanché Cell, A Carbon-Zinc Battery
French scientist Georges Leclanché invented a battery composed of a zinc anode with
a manganese dioxide cathode wrapped inside a porous material. The cell made use of an
ammonium chloride solution as the electrolyte. With carbon mixed into the manganese dioxide
cathode, this battery presented faster absorption and longer shelf life. Leclanché improved this
battery by substituting the liquid electrolyte into a pastier version, which resulted in the creation
of the first dry cell battery. It could be used in different orientations and transported without
spilling.
1886: Carl Gassner’s Version of The Leclanché Cell
Another version of dry cell was invented by Carl Gassner, who obtained a German
patent on a variant of the Leclanché battery. Gassner made use of Plaster of Paris to create the
ammonium chloride paste, mixed with a small amount of zinc chloride in order to prolong the
battery’s shelf life. As a result, the battery offered a more solid design and provided 1.5 volts
in full use. Gassner obtained a US Patent for this battery in 1887. Gassner’s idea paved the way
for the first mass-centric battery, powering portable electrical devices.
1899: The Nickel-Cadmium Battery
Waldermar Jungner, a scientist hailing from Sweden, has invented the first nickel-
cadmium battery (NiCD). This is a rechargeable battery containing nickel and cadmium
electrodes soaked in a potassium hydroxide solution. It is the first battery to make use of an
alkaline electrolyte, which in turn gives it the capability to produce better energy density than
the lead-acid battery.
1903: The Edison Battery
A famous American scientist, Thomas Edison, picked up the nickel-iron cell Jungner
designed and created another patented version of it. Edison made use of an alkaline cell with
iron as the anode and nickel oxide as the cathode. He also made use of potassium chloride as
conductor. The Edison battery was initially aimed for automobiles. However, it found greater
use in the industrial and railroad market, being strong enough to survive overcharged and
uncharged periods.
1955: The Arrival of Alkaline Batteries
Zinc-carbon batteries were the primary source of energy until the late 1950s. But this
battery type offers low shelf life and can easily be discharged. An engineer named Lewis Urry
was assigned to find a solution in extending the life of zinc-carbon batteries by the Eveready
21
Battery Company. Urry discovered that making use of alkaline in batteries offers more
advantage, supplying greater energy at higher currents compared to the zinc-carbon batteries.
1912: Lithium and Lithium-Ion Batteries
Gilbert Newton Lewis started with the experimentation on lithium batteries but
it was not until the latter part of the century that the first lithium batteries became commercially
available. Three important developments were vital to the creation of these batteries: the
discovery of the LiCoO2 cathode by John Goodenough (1980), the discovery of the graphite
anode by Rachid Yazami (1982) and the rechargeable lithium battery prototype produced by
Asahi Chemical, Japan. Sony commercialized the lithium ion battery in 1991.
Up to this point, scientists, inventors and battery companies are continually finding ways to
discover how to make use of our available resources to store electricity. The process of finding
ways to generate energy is probably never-ending, so it is best to keep our eyes open for
progress, innovation and ingenuity.
Service Life
Service life of a battery is the number of operating hours during which it satisfactorily operates
under normal conditions.
Factors affecting service life:
1. Quality of battery
2. Temperature during storage
3. Rate of discharge
4. Length of storage time
5. Temperature during discharge
6. Number and duration of on and off periods
Essential Parts of a Battery
1. Electrodes
a. anode (negative terminal) – oxidation occurs
b. cathode (positive terminal) – reduction occurs
2. Electrolyte – permits ionic conduction
3. Separator which physically separates the anode from the cathode but permits ions
to pass through.
4. Container
Classification of Batteries
1. Primary or non-rechargeable battery. This battery produces electricity as long as

active ingredients are present in the battery. Once active ingredients are consumed,
the battery is discharged.
22
Example: Dry cell
2. Secondary or rechargeable battery. The battery can be recharged by passing

current through it and can be used over and over again.
Example: Lead-acid storage battery; lithium-ion battery
Operation of Dry-cell Battery
A. Essential parts:
23
1. anode – zinc can

2. cathode – carbon rod
3. electrolyte – ammonium chloride in the form of a moist paste. Manganese
dioxide and powdered graphite are mixed with electrolyte.
4. Separator – porous paper (blotting paper)
B. Reaction during operation:
At anode:
Zn ➔ Zn++ + 2e- (oxidation)
(The 2 electrons go to external circuit and constitute the current produced.)
At cathode:
NH4Cl ➔ NH4+ + Cl-
2 NH4+ + 2e- ➔ 2 NH3 + H2 (reduction)
1. The 2 electrons come from the Zn electrode via the external circuit.
2. The H2 molecules accumulate as gas bubbles around the carbon rod
which prevents further reactions to occur.
3. MnO2 called a depolarization agent removes the H2 molecules by
this reaction:
H2 + 2 MnO2 ➔ H2O + Mn2O3
4. NH3 molecules react with Zn++ and Cl- to form Zn(NH3)4Cl2. The
above reactions occur as long as the supply of electrolyte is still
present. When the electrolyte is depleted, the battery cannot provide
as much current as before. Emf of fresh dry cell is 1.5 volts.
Operation of a Lead-acid Storage Battery
24
A. Essential parts:
1. Anode – Lead, Pb
2. Cathode – Lead (IV) oxide or plumbic oxide, PbO2
3. Electrolyte – dilute sulfuric acid solution
4. Separator – glass fiber spacers
B. Reactions during operation:
At anode:
Pb ➔ Pb++ + 2e- (oxidation)
The 2 electrons go to external circuit.
Pb++ + SO4= ➔ PbSO4 (s)
At cathode:
PbO2 + 4H+ + 2e- ➔ Pb++ + 2H2O (reduction)
Pb++ + SO4= ➔ PbSO4 (s)
The PbO2 accepts the electrons from the anode via the external circuit.
Over-all reaction: Pb + PbO2 + 2 H2SO4 ➔ 2 PbSO4 (s) + 2 H2O
1. Emf of one cell is 2.1 volts.

2. The H+ and SO4= ions come from the electrolyte.
3. As the anode and cathode reactions continue the sulfuric acid is
being used up and water is formed. The acid becomes weaker or less
dense.
4. Both Pb and PbO2 electrodes become coated with insoluble PbSO4.
5. The electrical output stops when both electrodes are thickly coated
with PbSO4 and the specific gravity of the H2SO4 solution is low.
C. Recharging of Lead-Acid Storage Battery
To recharge this type of battery, electricity from outside source is driven

through the battery to reverse the oxidation-reduction reactions.
Over-all reaction: 2 PbSO4 + 2 H2O ➔ Pb + PbO2 + 2 H2SO4
25
Nickel-Cadmium Battery
This is a rechargeable battery which can be used in place of primary batteries.
A. Essential parts:
1. Anode – Cadmium
2. Cathode – Nickel dioxide
3. Electrolyte – KOH solution (not involved in reactions)
At anode:
Cd (s) + 2 OH- ➔ Cd(OH)2 + 2e- (oxidation)
The 2 electrons go to outside circuit.
At cathode:
NiO2 (s) + 2 H2O + 2e- ➔ Ni(OH)2 + 2 OH- (reduction)
C. Characteristics of Ni-Cd battery:
1. Maximum Emf of one cell is 1.3 volts

2. Cell is sealed and does not leak; it comes in many sizes and voltage;
offers long service life; constant potential
26
3. More expensive
4. Low self-discharge rate
5. Over-charging will cause the battery’s capacity to decline
6. Contains toxic metals and is not environmentally friendly
Lithium-ion Battery
Lithium-ion batteries, also frequently referred to as li-ion, are the most popular and
regularly used batteries in today’s world. Ionic size plays a major role in determining the
properties of devices that rely on movement of ions. Although you may not realize what kind
of battery powers your mobile phone or laptop, chances are it’s a li-ion battery. These batteries
are a type of rechargeable battery and can be recharged over and over again. They do not require
regular maintenance and provide an extremely high energy density.
1. When the battery is being charged by an external source, lithium ions migrate from
the cathode to the anode where they insert between the layers of carbon atoms.
2. Lithium ions are smaller and lighter than most other elements, which means that
many can fit between the layers.
3. When the battery discharges and its electrodes are properly connected, it is
energetically favorable for the lithium ions to move from anode to cathode.
4. In order to maintain charge balance, electrons simultaneously migrate from anode
to cathode through an external circuit, thereby producing electricity. At the cathode,
lithium ions then insert in the oxide material. Again, the small size of lithium ions
is an advantage. For every lithium ion that inserts into the lithium cobalt oxide
cathode, a Co4+ ion is reduced to a Co3+ by an electron that has traveled through the
external circuit.
Essential parts:
1. Anode – graphite
2. Cathode – LiCoO2, lithium cobalt oxide
3. Electrolyte – a solution of lithium salts in a mixture of solvents (like
dimethyl carbonate or diethyl carbonate)
27
Oxidation takes place at the anode. There, the graphite intercalation

compound LiC6 forms graphite (C6) and lithium ions.
At anode:
LiC6 → C6 + Li+ + e-
Reduction takes place at the cathode. There, cobalt oxide combines with
lithium ions to form lithium-cobalt oxide (LiCoO2).
At cathode:
CoO2 + Li+ + e- → LiCoO2
Here is the full reaction (left to right = discharging, right to left = charging):
LiC6 + CoO2 ⇄ C6 + LiCoO2
C. Characteristics of Li-ion battery:
1. Small and thin with superior energy density; most smartphones use li-ion batteries
2. Quick to recharge, and fairly low self-discharge. A li-ion battery loses less than
5% of its full charge per month
3. Does not require a prolonged charge when new, compared to other rechargeable
batteries. One charge is all you need.
28
4. Maximum performance and efficiency offset high initial costs making it consumer
friendly
5. Environmentally friendly and safe
6. Not available in regular household sizes
7. Requires protection circuit to prevent over-heating and limit voltage
8. Overall capacity will slowly deteriorate over time, causing the device to lose its
charge quicker
9. Use a specific type of charger, requiring a user to purchase one or have one on
hand.
Other Battery Types:
29
30
31
Different Battery Sizes
Different battery sizes contribute

to the overall effectiveness of your
equipment, but it is important to
understand why. Generally, the larger the
battery is, the more capacity it has for
energy storage. So even though a big and
small battery are both rated at 1.5V, the
big battery stores more energy and
provides a longer battery life. Batteries are
extremely useful to us as consumers
because they convert stored chemical energy into electrical energy, eliminating the need for a
direct power source.
Common Battery Sizes
From thermometers and timers, to automatic paper towel dispensers and neon signs,
batteries are employed in some capacity in almost every environment. Although all batteries
serve the same purpose of providing us with instant, portable power, a large selection of
different sized batteries allows us to find the one that best suits a specific circumstance.
AA Batteries
Also known as “double A”, AA batteries are by far the most popular
battery size. Used in a multitude of applications, these batteries can
be purchased almost anywhere.
Double A batteries are generally what everyone pictures when they

think of standard replaceable batteries. Used in everything from
thermometers and staffing pagers to cordless phones, these batteries
are used extensively. AA batteries measure at 1.5V, and work well
for devices that require a somewhat high current draw, but are not in
constant use. They can also be used for devices like clocks that are
always on but use minimal energy.
AAA Batteries
Also known as “triple A”, AAA batteries are the second most
popular kind of battery. They are used for small toys,
thermometers, and calculators.
Triple A batteries are often used for small electronic devices such
as TV remote controls, kitchen timers, graphing calculators, and
bathroom scales. AAA batteries, like AA batteries, also measure at
1.5V, but generate less energy due to their smaller size. These
batteries are used primarily in small devices that don’t require a lot
of energy, like kitchen timers. The batteries will last a long time,
while still accomplishing their purpose. These compact batteries also power portion control
scales and thermometers.
32
AAAA Batteries
While “quadruple A”, or AAAA, batteries are not as common as

their AA and AAA counterparts, these thin batteries pack a
powerful punch.
These small but powerful batteries are often used in LED penlights
and laser pointers. They are also frequently used in small devices
such as glucose meters, hearing aid remote controls, and powered
computer styluses.
C Batteries
These heavy-duty batteries are m ainly used for toys, flashlights,

and portable radios.
Many automatic hand sanitizer dispensers require the use of these

1.5V batteries. Perfect for heavy-duty applications where batteries
require frequent use, you can be sure that your device is operating
with safe, reliable power. These batteries are also frequently used
in restrooms that utilize battery powered flush sensor
D Batteries
Used for devices that require an extended period of power time, these
batteries work best in large flashlights, stereos, and hands-free soap
or paper towel dispensers.
Powering most automatic paper towel dispensers, D batteries are

essential. These large, bulky batteries provide hours of use and power
a variety of commercial, heavy-use devices, like hands-free sensor
faucets, air freshener systems, and soap dispensers.
33
9V Batteries
Generally known for its rectangular shape, the 9-Volt

battery is used in devices that require high voltage and lots
of power.
9V batteries work extremely well for devices like infrared

thermometers, battery powered temperature alarms, and
electronic portion scales. These products may all encounter
extreme temperatures from food, walk-in coolers, or other
kitchen equipment. 9V batteries are exceptionally durable and
offer outstanding performance, working in environments
from 0 to 130 degrees Fahrenheit.
CR123A Batteries
Packed with power, this battery is frequently used for tactical
equipment, wireless security, and home automation.
Although significantly shorter in length than a AA battery, the

CR123A battery generates 3 volts—twice the voltage of a AA
battery. These batteries deliver a huge amount of power while
maintaining a relatively small size. Ideal for devices that require
a lot of power, like LED flashlights, they ensure maximum
performance. This battery will last longer than most, thanks to
its large power-to-size ratio.
23A Batteries
This small battery is commonly used in small devices such as

garage door openers, specialized medical devices, watches, or
remotes.
Delivering 12 volts of power, it is used in applications that

require infrequent but powerful bursts of energy. Previously used
in photoflash film cameras, these batteries are now used
primarily for garage door openers, wireless doorbells, and
keyless entry devices.
34
CR2032 Batteries
This small round battery offers a lot of power in a compact size, making
it unique compared to most other batteries.
At 3 volts, the CR2032 battery is commonly used in watches, calculators,

toys, and different medical devices. These batteries provide long-lasting,
reliable power and have a very high weight-to-power ratio. Used in wrist
watches and slim, compact thermometers, this battery is practically
weightless while providing hours of use.
Most consumers have a vague sense that it might be

environmentally unsound or even dangerous to throw
batteries in the trash. However, not many people
know which batteries require special handling, how
to properly dispose of them, and most
importantly where to properly dispose of batteries.
Handling instructions by battery type:
Alkaline Batteries: alkaline batteries are the most common type of batteries in battery
powered household products and are classified as non-hazardous waste. This means that you
can safely dispose of alkaline batteries in your normal household trash.
Button Cell Batteries: also, commonly called watch batteries, button cell batteries have
several different chemistries, all of which are label as hazardous and must be disposed of at a
proper hazardous waste reclamation facility.
Silver Oxide: silver oxide batteries are one type of button cell battery and are technically
hazardous waste. However, the law permits an exception for households because of the small
amount of silver oxide battery waste they generate. Therefore, under current regulations,
disposal of silver oxide batteries in normal household waste is permitted.
Carbon Zinc Batteries: carbon zinc batteries are classified as non-hazardous waste by the
government and be can safely disposed of in your normal household trash.
Lead-Acid Vehicle Batteries: any lead acid battery, like the one in your car, is considered
hazardous waste and must be disposed of correctly. Most locations that sell vehicle batteries
will also take them for recycling, though they may charge you a fee. On the other hand,
businesses that recycle metals may be willing to pay you for your burned-out car battery.
35
Lithium Ion Batteries: lithium ion batteries are classified as non-hazardous and can be
discarded as part of your normal household waste collection. However, these batteries can also
be recycled.
Rechargeable Nickel Cadmium (Ni-Cd): rechargeable nickel cadmium batteries are

classified as hazardous. These batteries must be disposed of at a proper hazardous waste
reclamation facility.
Rechargeable Nickel Metal Hydride (Ni-Li or Ni-Hydride): rechargeable nickel metal

hydride batteries are labeled non-hazardous by the government and may be discarded in
standard household waste or recycled at a certified location.
Find out where to dispose of hazardous and recyclable batteries:
Your waste disposal company or your local government may also have programs to reclaim
batteries.
Additional Battery Disposal Tips:
Avoid disposing of large quantities of batteries together. Some batteries will retain a
residual charge and if enough of them come into contact in the trash they can heat up,
potentially causing chemical leaks, explosions, or fires.
While it seems like it should go without saying, never burn batteries. The volatile and
potentially hazardous chemicals in batteries can build up enough pressure to explode if heated.
To avoid chemical leaks never disassemble or crush a battery.
36
PROGRESS CHECK
(May be given separately by your teachers)
37
REFERENCES
Balacuit, G. G., Hermosura, A. J., Dingcong, M. G., Ralios, M. C., Tortosa, H. L., &
Andres, J. (1990). Handbook of General Chemistry I (1st ed.).
Brown, T. L., Jr., H. E., Bursten, B. E., Murphy, C., Woodward, P., Langford, S., Sagatys, D.,
& George, A. (2013). Chemistry: The central science. Pearson Higher Education AU.
https://www.upsbatterycenter.com/blog/history-batteries-timeline/#prettyPhoto
https://www.webstaurantstore.com/guide/923/batteries-buying-guide.html
https://jenesisproducts.com/how-to-dispose-of-batteries-properly/

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TECHNOLOGICAL UNIVERSITY OF THE PHILIPPINES VISAYAS

Capt. Sabi St., City of Talisay, Negros Occidental

College of Engineering Technology

DEPARTMENT: CHEMICAL ENGINEERING TECHNOLOGY

FRITZIE B. ASUNCION, MT GREDA G. BALACUIT, RCh

MA. AGNES G. DINGCONG ALPHA J. HERMOSURA, RChE

EDELYN G. LOBATON, RChE

T - Transparent and participatory governance

This is the second part of a two-semester course on the fundamental concepts

LO1: Perform general chemistry laboratory experiments following specified

LO2: Correctly use common laboratory glassware and equipment to make

GENERAL GUIDELINES/CLASS RULES

Name of Professor/Instructor official e-mail add

Note: For CLASS MAYORS

The student will be graded according to the following:

Average of examinations - 40%

Pre-lim Grade : [(Prelim exam x 0.40) + (Assessment: 50% Quizzes+ 50%

Endterm Grade : [Endterm exam x 0.40) + (Assessment: 50% Quizzes+ 50%

Final Grade : Prelim Grade + Midterm Grade+ Endterm Grade

The passing grade for this course is 5.0.

Week No.: _10-11

Electrochemistry is an important component of General Chemistry since it is one of the

Any electrochemical process involves oxidation-reduction reaction in which electrons are

Example of Oxidation-Reduction or Redox reaction:

A clean copper wire placed in a colorless solution of silver nitrate

Oxidation : Cu0(s) ➔ Cu+2(aq) + 2e-

Reduction : Ag+(aq) + 1e- ➔ Ag0(s)

Electrolytes and Non-electrolytes

An essential component of an electrochemical cell is the electrolyte. Electrolyte is

Mechanisms Involved in the Formation of Ions

1. Dissociation is the separation of ions from electrovalent compound by the action of a

The classification of electrolytes is based on experimental observations. Solutions are

Colligative Properties of Solutions of Electrolyte and Non-electrolyte

1. Effect in freezing point of pure solvents

2. Effect in the boiling point of pure solvents

The process whereby a current of electricity is used to bring about oxidation-reduction

Electrolysis is carried out in an electrolytic cell which consists of two electrodes in a

A. Components of Electrolytic Cell

1. electrodes - a pair of conducting metal

B. The Basic Set-up of an Electrolytic Cell

C. Operation of Electrolytic Cell

At the anode: X- ➔ X + 1e- (oxidation)

At the cathode: M+ + 1e- ➔ M (reduction)

X- = negative ion from electrolyte

Cathode reaction: H+ + 1e- ➔ H0

Over-all cell reaction: 2 H2O ➔ O2(g) + 2 H2(g)

Electroplating is a process in which a coating of metal is added to a conductor with

10 Daily Life Examples of Electroplating

Here are the daily life examples of electroplating:

Nickel plating is done on a metal surface to reduce friction in

Many household items including silverware retain their elegance and

Electroplating is used to improve the overall quality and longevity of a

Electroplating is also used to plate desired characteristics on the metals

Electroplating is used in various commercial appliances. Nickle is used

10. Aerospace and Aviation

Anodizing is an electrochemical process that converts the metal surface into

When the current is applied, the water in the

The acid in the electrolyte tries to dissolve this

Once the required thickness of anodic film is