ROEVER ENGINEERING COLLEGE
DEPARTMENT OF CHEMISTRY
SECOND SEMESTER
ENGINEERING CHEMISTRY-II
UNIT-I: WATER TECHNOLOGY
1
PART A
1 . Explain the term “Carbonate Hardness and “Non-Carbonate Hardness”. (OR) What is non carbonate
hardness? How does it differ from carbonate hardness?
 Carbonate hardness is due to the presence of bicarbonates of calcium and magnesium. It can be
removed by boiling the water and adding lime to the water.
 Non carbonate is due to the presence of chlorides and sulphates of calcium and magnesium. It
cannot be removed by boiling the water. But it can be removed by Lime soda process and zeolite
process.
2. What is hardness? How hardness is identified?
Hardness is the property or characteristics of water which doesn’t produce lather with soap. It
can be detected in two ways.
 When the water is treated with soap solution, if it prevents lathering and forms white
precipitate, the water contains hardness.
 Water containing hardness gives wine red colour with Eriochrome Black-T indicator at pH
9-10.
3. Define boiler feed water.
The water fed into the boiler for the production of steam is called boiler feed water.boiler
feed water should be free from turbidity,oil,dissolved gases,alkali and hardness causing substances.
4. What is role of phosphate in the internal treatment of water?
Scale formation can be avoided by adding sodium phosphate. It is used in high pressure
boilers. The phosphate reacts with Ca 2+ and Mg 2+ salts to give soft sludge’s of calcium and
magnesium phosphates.
3CaSO4 +2Na3PO4 → Ca3(PO4)2+3Na2SO4
5. Compare scale and sludge.
SLUDGE
SCALE
Sludge ia loose,slimy and non- Sacle is hard,adherenr coating
adherent precipitate.
The mail sludge forming substances The main scale forming substances
are MgCO3,MgCl2 .
are Ca(HCO3)2, CaSO4
6. Define and Distinguish between hard and soft water.
 Water which doesn’t produce lather with soap solution but produces white precipitate
is called hard water.
 Water which produce lather with soap solution is called soft water.
Hard water
soft water
Hard water does not produce lather
with soap solution
It gives wine red colour with EBT
indicator.
soft water produce lather with soap
solution
It does not give colour with EBT
indicator.
7. Mention the units used for expressing hardness of water.
Parts per million: the number of parts of CaCO3 equivalent hardness per 10 6 parts of water.
Milligrams per litre (mg/lit): the number of milligrams of CaCO3 equivalent hardness per 1 litre
of water.
Clarke’s degree (0Cl): the number of parts of CaCO3 equivalent hardness per 10 5 parts of water.
French degree (0Fr): the number of parts of CaCO3 equivalent hardness per 70,000 parts of
water.
8. What is calgon conditioning? How is it functioning in water treatment?
Calgon is sodium hexa meta phosphate Na2[Na4(PO3)]6.This substance interacts with calcium ions
forming a highly soluble complex and thus prevents the precipitation of scale forming salt.
CaSO4+Na2[Na(PO3)]6
→ Na2[Ca(PO3)]6+2Na2SO4
9. Why phosphate conditioning is preferred over carbonate conditioning?
Phosphate conditioning is used for both acidic and alkaline water in high pressure boilers and
carbonate conditioning is used for low pressure boilers.So phosphate conditioning is preferred over
carbonate conditioning.
10. Why a soft water need not be demineralised water but a dimeneralised water is always soft water?
The soft water obtained from lime soda or zeolite process does not contain Ca 2+ and Mg 2+ ions but
contain ions like Na+,K+,SO42-,Cl - etc. But demineralised water produced from ion exchange process
does not contain both cations and anions. So soft water is not demineralised water but demineralised
water is soft water.
11. What is priming and foamimg? How can it be prevented?
The process of production of wet steam is called priming.It can be prevented by controlling the
velocity of steam and having good boiler design.
The formation of stable bubbles above the surface of water is foaming.It is prevented by adding
coagulants like sodium aluminate,aluminium hydroxide and also by adding anti-foaming agents.
12. Define caustic embrittlement.
Caustic embrittlement means intercrystalline cracking of boiler metal.It can be prevented by using
sodium phosphate as softening agent instead of sodium carbonate.
PART- B
1. What are boiler troubles? How are they caused? Suggest steps to minimize the boiler troubles. (OR)
Discuss in detail the problems caused due to usage of hard water in boilers.The water fed into the boiler
for the production of steam is called Boiler feed water. Boiler feed water should be free from
turbidity,oil,dissolved gases,alkali and hardness causing substances. If hard water obtained from natural
sources is fed directly into boilers,then boilers troubles may arise. Some of the boiler troubles are



Scale and sludge
Boiler corrosion
Priming and foaming
Caustic embrittlement
Scale: If the precipitate forms hard and adherent coating on the inner walls of the boiler, it is called
scale. Scales are formed by substances like Ca(HCO3)2.
Sludge:If the precipitate is loose ans slimy it is called sludge.Sludge are formed by substances like
MgCl2,MgCO3,MgSO4 and CaCl2.
Priming:Priming is the process of production of wet stream.
Causes:




High steam velocity
Very high water level in boiler
Sudden boiling of water
Very poor boiler design
Prevention:




Controlling the velocity of steam
Keeping the water level lower
Good boiler design
Using treated water
Foaming:The formation of stable bubbles above the surface of the water is called foaming.
Cause:


Presence of oil, and grease
Presence of finely divided particles
Prevention:


Adding coagulants like sodium aluminate,aluminium hydroxide
Adding anti-foaming agents like synthetic polyamides.
Caustic embrittlement: Caustic embrittlement means intercrystalline cracking of boiler metal.
Boiler water usually flows into the minute hair cracks and crevices usually present on the boiler material
by capillary action and dissolves the surrounding area of iron as particularly stressed parts like sodium
ferroate.
This causes brittlement of boiler parts like bends,joints,rivets,etc.
Prevention:


Using sodium phosphate as softening agent instead of sodium carbonate.
By adding tannin,lignin to the boiler water which blocks the hair cracks.
2.What are zeolites? How do they function in removing the hardness?
Zeolites are naturally occurring hydrated sodium aluminosilicates.Its general formula is
Na2O.Al2O3.xSiO2.yH2O(x=2-10,y=2-6).Natural zeolites are green sand and non porous.The synthethis
form of zeolite is known as permutit represented as Na2Ze.The sodium ions which are loosely hale
inNa2Ze are replaced by Ca2+ and Mg2+ ions present in the water.
Process:
When hard water is passed through a bed of sodium zeolite, kept in a cylinder, it exchanges its sodium
ions with Ca2+ and Mg2+ ions present in the hard water to form calcium and magnesium zeolites. The
various reaction taking place during softening process are
Ca(HCO3)2 + Na2Ze
→
CaZe + 2NaHCO3
Mg(HCO3)2 + Na2Ze
→
MgZe + 2NaHCO3
CaSO4 + Na2Ze
→
CaZe + Na2SO4
MgSO4 + Na2Ze
→
MgZe + Na2SO4
CaCl2 + Na2Ze
→
CaZe + 2NaCl
MgCl2 + Na2Ze
→
MgZe + 2NaCl
The softened water is enriched with large amount of sodium salts which donot cause any hardness but
cannot be used in boiler.
Regeneration:
After some time zeolite gets exhausted. The exhausted zeolite is again regenerated by treating with
NaCl.
CaZe + 2NaCl
→
Na2Ze + CaCl2
MgZe + 2NaCl
→
Na2Ze + MgCl2
3. What is desalination? Explain reverse osmosis method.
The process of removing common salts from brackish or saline water is called desalination.
Water is graded into 3 types
Fresh water has less than 1000 ppm dissolved solids.
Brackish water has >1000 ppm but <35000ppm of dissolved solids.
Sea water has >35000ppm of dissolved solids.
Reverse Osmosis:When two solutions of different concentrations are separated by a semi permeable
membrane, solvent flows from low concentration side to high concentration side. This process is called
Osmosis. Osmotic pressure is the driving force involved in this process.f hydrostatic pressure in excess
of osmotic pressure is applied, solvent flow is reversed. That is solvent flows from higher concentration
side to lower concentration side. This process is reverse osmosis. When pressure is applied on he salt
water, the pure water flows through the semi permeable membrane and leaving the dissolved solids. This
process is also known as super filtration. Cellulose acetate and synthetic polyamide are used as semi
permeable membranes.
Advantages:




Reverse osmosis removes ionic as well as non ionic impurities.
Life time of membrane is high and can be replaced within few minutes.
Operating cost and maintenance cost is low.
It removes colloidal silica which is not removed by demineralization.
4. How is internal treatment of boiler water carried out?
Internal treatment involves the removal of scale forming substance, which were not completely removed in
the external treatment, by adding chemicals directly into the boiler. This chemicals are also called as boiler
compounds.
Carbonate conditioning:Scale forming can be avoided by adding Na2CO3 to the boiler water.It is used only
in low pressure boilers.The scale forming salt like CaSO4 is converted into CaCO3,which cane be removed
easily.
CaSO4+Na2CO3 → CaCO3+Na2SO4
Phosphate conditioning:Scale formation can be avoided by adding sodium phosphate.It is used in high
pressure boilers.The phosphates react with Ca2+ and Mg2+ to give Ca and Mg phosphates.
3CaSO4+2Na3PO4 → Ca3(PO4)2 +3Na2SO4
Generally 3types of phosphates are employed.



Trisodium phosphate - used for too acidic water
Disodium hydrogen phosphate - used for weakly acidic water.
Sodium dihydrogen phosphate - used for alkaline water
Colloidal conditioning:
It is an internal conditioning method of using tannin,agar-agar, kerosene etc.into boiler water to remove
scale forming substanced which are not removed by external treatment.
Calgon conditioning:
It is an internal conditioning method using sodium hexa meta phosphate into boiler water to remove scale
forming substances which are not removed by external treatment.
CaSO4+Na2[Na4(PO3)6 → Na2[Ca2(PO3)6]+2Na2SO4
5 .What is external treatment method. Explain demineralization (or)Ion exchange process.
External treatment involves the removal of hardness causing salts from water before feeding into boiler.The
important methods by which hard water can be softened are



Lime soda process
Zeolite process
Demineralization (or) Ion exchange process
In this process, resins are used as softening or ion exchange materials and remove completely all cations and
anions. The resins are porous, insoluble, cross linked, long chain organic polymers with functional groups
capable of exchanging ions.they are two types:
Acidic: exchanging their H+ ions with cations
Basic: exchanging their OH- ions with anions
Cation exchange resin:
Resins contain sulphonic functional group.They are capable of exchanging their H+ ions(cation)with other
cations of hard water.This is represented by RH2.
Examples:
Sulphonated coal,Sulphonated polystyrene,Phenol formaldehyde Resin
Anion exchange resin:
Resins contain basic functional groups –NH2 &-NR3OH .they are capable of exchanging anions.They are
simply represented by R’(OH)2
Example:
Urea formaldehyde resing,Quaternary ammonium salts
Process: The hard water is allowed to pass through cation exchange column.
The cation exchange resin absorbs cations like ca2+ and Mg2+ and release equivalent amount of H+ ions.
CaCl2 + RH2 → RCa + 2HCl
MgSO4 + RH2 → RMg + H2SO4
Cation free water is passed through an anion exchange coloumn,Anion exchange resin absorbs anions like
SO42-,Cl- from water and release equivalent amount of OH- ions.
R’(OH)2 + 2HCl→ 2R’Cl + 2H2O
R’(OH)2 + 2H2SO4→ 2R’SO4 + 2H2O.The resultant water from anion exchanger is free
from cations and anions. This water is called demineralised water.
Regeneration:
When cation exchange resin is exhausted, it can be regenerated by passing a solution of
dil.HCl(or)dil.H2SO4
RCa + 2HCl
→ RH2 + CaCl2
RMg + 2HCl
→ RH2 + MgCl2
When anion exchange resin is exhausted it can be regenerated by passing a solution of dil.NaOH
R’SO4+2NaOH → R’(OH)2 + Na2SO4
Advantages:


Highly acidic or alkaline water can be treated in this method
very low hardness water id obtained.
Disadvantage:


Turbid water cannot be treated
Equipment and chemicals are costly
6.Describe boiler corrosion.
*************************
UNIT-II: ELECTROCHEMISTRY AND CORROSION
PART-A
1. What is electrode potential?
The tendency of an electrode to lose or gain electrons, when it is in contact
with its own ions.
2. What is an electrochemical cell?
A device used to convert the chemical energy produced in a redox reaction
into electrical energy.
3. Define a reference electrode?
The tendency of an electrode to lose electrons, when it is in contact with
solution of its own ions.
4. What do you mean by electrode potential (E)?
It is the tendency of an electrode in a half cell to lose or gain electrons when it is
in contact with the solution of its own ions.
5. What are reduction and oxidation potentials?
Reduction potential is the tendency of an electrode in a half cell to gain electrons
and oxidation potential is the tendency of an electrode in a half cell to lose electrons.
6. What do you mean by standard electrode potential (E°)?
It is the electrode potential of a metal in contact with its ions when the
concentration of ions is 1 M (1 molar).
7. What is a salt bridge?
It is an inverted U-tube containing an electrolyte (e.g., KC1, KNO3). It connects
(acts as a bridge) the solutions of the two half cells.
8. What are reference electrodes?
These are the electrodes whose potential is constant and independent
of the composition of the contacting solution.
The most widely used are saturated calomel electrodes (G = + 0.246 V) and
the silver-silver chloride electrode (e = + 0.222 V).
9. Define the electrochemical series?
When the standard reduct ion potent ials of the electrodes are arranged in an
increasing order, the series so obtained is known as electrochemical series.
10. What is corrosion?
The destruction of metals or alloys by the action of gaseous atmosphere,
water or any other reactive liquid medium is known as corrosion.
11. Mention the conditions for wet corrosion to takes place?
i) When two dissimilar metals are in contact with each other in presence of
aqueous solution or moisture, electrochemical or wet corrosion occurs.
ii) When a metal is exposed to an electrolyte with varying amount of
oxygen, then also wet corrosion takes place.
12. What is Pilling Bedworth ratio? Give its significance?
The ratio of the volume of oxide film formed to the volume of metal
consumed is called Pilling Bedworth ratio. It gives an idea about whether the
oxide film formed on the metal surface is protective or non-protective.
13. What is dry corrosion? Give examples.
Dry corrosion is the direct chemical attack of metals by the gases such as O2, CO2,
SO2, H2O etc.
Eg: - i) Tarnishing of silver articles in H2O gas.
ii) Action of dry HCl on iron surfaces.
14. What is wet corrosion?
It is a type of corrosion which occurs when a conducting liquid is in contact with
metal (or) two dissimilar metals or alloys either immersed or partially dipped in a
solution.
15. What is galvanic corrosion?
When two metals are electrically connected and exposed to an electrolyte, the
metal higher in electrochemical series undergoes corrosion. Eg; Zn-Cu couple, Zn
gets corroded.
16. What is pitting corrosion?
Pitting is a localized attack which results in the formation of a hole around which
the metal is relatively unattached. The mechanism involves setting up of differential
aeration cell.
17. Name the factors which affect corrosion.
i) Air and Moisture
ii) Electrolyte in water
iii) pH of the medium
iv) Presence of corrosive gases
v) Presence of impurities in a metal.
18. A steel screw in a brass marine hardware corrodes. Give reason.
This is due to galvanic corrosion. Iron which is higher in the emf series becomes
anodic and is corroded. Brass which is present lower in series acts as cathodic and is
not corroded.
19. Iron corrodes under drops of salt water. Explain.
This is due to differential aeration. Areas of iron covered by drops, having poor
access to oxygen, become anodic with respect to other areas which are freely
exposed to air. Due to electrochemical corrosion, the areas under drops undergo
corrosion, while the freely exposed parts remain unaffected.
20. The rate of metallic corrosion increases with increase in temperature. Give
reason.
With increase of temperature of the environment, the rate of reaction as well as
rate of diffusion increases, thereby corrosion rate increases.
21. Iron corrodes faster than aluminium, even though iron is placed below
aluminium in emf series. Why?
This is because aluminium forms a non-porous, very thin, tightly adhering
protective oxide film (Al2O3) on its surface and this film does not permit corrosion to
occur.
22. Rusting of iron is quicker in saline water than in ordinary water. Give reason.
The presence of sodium chloride in saline water leads to increased conductivity of
water layer in contact with the iron surface, thereby corrosion current increases and
rusting is speeded up.
23. What is cathodic protection? Mention its two applications.
Cathodic protection is the reduction or prevention of corrosion by making
metallic structure as cathode in the electrolytic cell. This can be done by either using
sacrificial anodic (or) impressed current cathodic method.
They give protection to cables, pipelines, ship hulls from marine corrosion.
24. What is impressed current cathodic protection?
It is a method in which an impressed current (greater than corrosion current) is
applied in opposite direction to nullify the corrosion, thereby converting the corroding
metal from anode to cathode.
25. What are corrosion inhibitors? Give examples.
Corrosion inhibitors are substances which are added to the corrosive environment
to decrease the corrosion rate.
Eg. Anodic inhibitors – phosphates & chromates.
Cathodic inhibitors – aniline and its derivatives.
26. What is the role of pigment in paint? Give examples.
i) Pigments are solid substances and they provide color to the paint.
ii) They provide capacity to the paint.
iii) They give protection to the paint film by reflecting harmful UV radiation.
Eg. Green – chromium oxide
Blue – Prussian blue.
27. What is meant by electroplating?
Electroplating is the process by which the coating metal is deposited on the base
metal by passing a direct current through an electrolytic solution containing the
soluble salt of the coat metal.
28. What is meant by electroless plating?
Electroless plating is the technique of depositing a noble metal from its salt
solution on a catalytically active surface of the metal to be protected by using a
suitable reducing agent without using electrical energy.
Metal ion + reducing agent _ Metal + oxidized product.
29. What is meant by anodizing?
Anodizing is a process by which a thick oxide coating can be produced on the
base metal by making it as anode in the electrolytic cell. The electrolytes used to assist this process are
oxalic acid, chromic acid etc.
PART B
1. Explain the mechanism of oxidation corrosion.
2. Write notes on wet corrosion.
3. Explain galvanic type corrosion and differential aeration corrosion?
4. How do you control the corrosion.
5. What are paints? Mention its constituents. Explain the functions of various
constituents.
6. Write notes on i) Electroplating and ii) Electrolessplating.
ROEVER ENGINEERING COLLEGE – PERAMBALUR
TWO MARKS QUESTION BANK
UNIT - III
NON-CONVENTIONAL ENERGY SOURCES AND STORAGE DEVICES
1.
What are non-conventional energy sources?
Non-conventional energy sources are the renewable energy sources which are not
conventionally used for power generation. (eg) Wind energy, solar energy and tidal energy.
2.
Write any one nuclear fusion and fission reaction.
a) Nuclear fission is the process of splitting of a heavy nucleus with some projectiles into
two smaller nuclei with simultaneous liberation of a large amount of energy. It takes
place at ordinary temperatures and chain reaction occurs.(eg)
235
U92 +1n0
236
U92
144
Xe54 + 90Sr38 + 2 0n1 + Energy
b) Nuclear fusion is the process of combination of light weight nuclei to form heavy nucleus
with the simultaneous liberation of large amount of energy. It takes place at very high
temperatures and chain reaction does not occur.
(eg)
3.
What are the characteristics of Nuclear fission (or) Mention few characteristics of Nuclear
fission.
Characteristics of Nuclear Fission:
Heavy nucleus like U235 or Pu239 is split into two nuclei
Two or more neutrons were emitted
Very large amount of energies are liberated due to the conversion of mass
into energy.
iv)
Fission fragments are radioactive and emit and radiations.
v)
The atomic mass of fission products ranges from 70 to 160
vi)
Chain reaction occurs since fission product contains neutrons which cause
fission of other nuclei.
vii)
Chain reaction can be controlled using cd113 and B10
viii)
For chain reaction to take place, the number of neutrons resulting from single
fission (known as Multiplication factor) should be greater than or equal to 1.
What are the characteristics of Nuclear fusion
i)
ii)
iii)
4.
Characteristics of Nuclear Fusion:
i)
ii)
Nuclear fusion is the process of combination of light weight nuclei to from heavy nucleus
It takes place at very high temperature (around 106K).
iii)
Few Positrons are emitted
iv)
It cannot be performed under controlled conditions.
v)
Large amount of energies are liberated due to the conversion of mass into energy.
Illustrate the differences between nuclear fission and fusion reactions?
5.
Differences between Nuclear Fission and Nuclear Fusion
S.No.
1.
2.
3.
4.
5.
6.
6.
NUCLEAR FISSION
NUCLEAR FUSION
Nuclear
Fission
takes
place Nuclear Fusion takes place at very high
spontaneously at ordinary temperature
temperature.
It is process of breaking a heavy It is a process of fusing light weight nuclei.
nucleus.
Radioactive rays are emitted
Radioactive rays are not emitted
Chain reaction occurs
Chain reaction does not occur.
Neutrons are emitted
Positrons are emitted
It can be performed under controlled It cannot be performed under controlled conditions.
conditions.
Give any one nuclear fission reaction, mention the factors that impede the nuclear chain
reaction?
235
92U
+ 0n1
236
92U
Followed by
236
92U
56Ba
144
+ 36Kr89 + 30n1 + 177 MeV
Conditions for maintaining chain reaction (or) The factors that impede the nuclear chain
reaction:
The neutrons produced in the fission reaction should not be lost.
7.
i)
By escape of neutrons from the active material without causing fission
ii)
By absorption of neutrons by non-fissionable atoms like 238U.
Furnish the sequence of reactions in proton cycle nuclear fusion.
The sequences of reactions in proton cycle nuclear fusion are given below.
1
1H
+ 1H1
2
1H
+ +1e0 + energy
1
1H
+ 1H2
2He
3
+ energy
2He
4
+ 2 1H1 + energy
3
2He
+ 2He3
Two protons combine to form a deuterium nucleus which then combines with another proton
to yield helium (3). Two helium (3) nuclei combine to form helium (4) and the energy released is 26.
7 Mev.
8.
Why do fission and fusion reactions produce large quantities of energy?
Enormous amount of energy is released during nuclear fission and fusion reactions due to
the loss in mass which is converted into equivalent amount of energy in accordance with Einstein’s
mass energy equation.
E = mc2
ms-1(3`108ms-1)
9.
E - Energy in joules, m - Equivalent of mass in kg, c – Velocity of light in
What is nuclear chain reaction?
A nuclear fission reaction in which the neutrons from the previous step continue to repeat
and propagate the reaction is called nuclear chain reaction.
10.
Which isotope of uranium is used in nuclear reactor?
The isotope of uranium is used in nuclear reactor is 92U235
11.
Define critical mass, super critical mass and sub critical mass.
The minimum amount of fissionable material (92U235) required for continuing the nuclear
reaction is called critical mass. The critical mass of (92U235) lies between 1 kg to 100 kg.
If the mass of the fissionable material is more than the critical mass it is called super critical
mass. If the mass of the fissionable material is smaller than the critical mass it is called sub critical
mass.
12.
What are moderators? Give some examples.
Moderator is substances which are used to slow down the neutrons. They are used reduce
the kinetic energy of fast moving neutrons (1 Me V) to slow neutrons (0.25 eV).
(eg) Graphite, beryllium, water and heavy water
13.
Why are the electrodes used in fuel cells porous?
The electrodes used in fuel cells are porous for providing large surface area for reaction
zone with minimum hinderance for the mass transport. Thus it facilitates smooth access for the
reactants and prompt removal of products.
14.
What is fissile nucleides and fertile nucleides ?
Fissile and Fertile Nuclei’s
The fissionable nuclei’s like U235 and Pu239 are called fissile nuclei’s.
The non fissionable nuclei’s like U238 and Th232 are called fertile nuclei’s
15.
What is nuclear energy? Explain with a suitable example.
Enormous amount of energy is released during nuclear fission is called nuclear energy.
For example, when a heavy nucleus (U235) is bombarded by a high speed neutron, it is splitted into
two smaller nuclei with simultaneous liberation of a large amount of energy.
235
92U
+ 0n1
56Ba
144
+ 36Kr89 + 30n1 + 177 MeV
16.
What is a nuclear reactor? What are the general components of a nuclear reactor?
A nuclear reactor or pile is an equipment or arrangement used for carrying out fission reaction
under controlled conditions. The liberated energy can be utilized for purposes like generation of
electricity.
1.
2.
3.
4.
5.
6.
Fuel rods
Control rods
Coolants
Moderator
Pressure vessel
Protective shield
Turbine
What is light water nuclear power plant?
7.
17.
Light Water nuclear power plant is a reactor in which U235 fuel rods are submerged in water.
Here, water acts as coolant and a moderator.
18.
What is a breeder reactor?
BREEDER REACTOR: It is a reactor that converts non-fissionable material (U238) into
fissionable material (Pu239). The neutron absorbed by 238U a non-fissionable material converted to 239Pu,
a fissionable material. 239Pu is a man made nuclear fuel and is known as secondary fuel.
92U
238
+ 0n1
239
94Pu
+ 2 0e-
A reactor with a conversion factor above unity is known as breeder reactor. Conversions
factor is the ratio of the number of secondary fuel atoms produced to the number of primary fuel atoms
consumed. Such reactors are of great significance and commercial importance, because such a
reactor not only replaces the fuel burnt but also produces fuel more than what is used.
19.
How will you obtain wind energy? Mention its drawbacks? What is wind energy? How is it
harnessed?
Moving air is called wind. The energy obtained from the force of the wind is called wind
energy. Wind energy is also called as Primary energy resource because it is obtained from the
environment. Wind mill contains blades which are connected to a generator through a shaft. Initially
electricity is required for rotating the blade. When there is sufficient flow of wind, it rotates the blades
continuously and electricity produced. Wind mills are capable of producing 100kW electricity
Drawbacks of wind energy conversion
(i)
(ii)
(iii)
(iv)
20.
Installation of wind mill involves high capital cost.
When the flow of air is not continuous, we cannot get current continuously
Wind turbines interfere with TV and radio signals.
The wind farms produce unbearable noise.
Write any four methods adopted for harnessing wind energy?
Methods used for harnessing wind energy are
1. Wind mills
2. Wind farms
3. Ladder Mill
21.
4. Wind Mill
5. Sky Wind Power
6. Kite ship
7. Sky sail
What are the merits of wind energy?
Advantages (merits) of wind energy conversion
22.
(i)
It is more economic
(ii) It does not cause pollution during energy generation
(iii) It is a renewable energy source
(iv) Windmills can be built on shore and offshore.
Give a note on solar cell and its featuers.
Photogalvanic cell is a cell that converts the solar energy (energy received from sun) directly
into electrical energy. When a large number of photogalvanic cells are interconnected, solar cells are
formed. Solar cells consist of a p-type semiconductor (such as Si doped with B) and n-type semi
conductor (such as Si doped with P). They are in close contact with each other. Solar rays fall on lower
layer, kinetic energy of electrons increases and entrapped in upper layer. Potential different between
layers is created which produces electricity.
23.
What do you mean by solar energy conversion?
Solar energy conversion is the process of conversion of solar energy from sun into another
form of heat or light energy. Solar energy is used for providing low temperature heat.
24.
1.
Thermal conversion
2.
Photo conversion
Explain thermal conversion and photo conversion?
(a) Thermal conversion :
It involves absorption of thermal energy in the form of IR radiation
and is useful for heating buildings, water and refrigerator. (eg) Solar heat collectors: Solar heat
collectors consist of natural material like stones (or) bricks which can absorb heat during the day time
and release it slowly at night.
b) Photoconversion:
Photoconversion involves conversion of light energy directly into electrical energy with the
help of Photogalvanic cell or solar cell. Photogalvanic cell is a cell that converts the solar energy
(energy received from sun) directly into electrical energy. When a large number of photogalvanic cells
are interconnected, solar cells are formed.
25.
What are the applications of solar cells?
Applications:
i)
ii)
iii)
iv)
Solar cells are used in boilers to produce hot water for domestic and industrial uses.
Solar cells can be used for lighting purposes.
Solar cells are non-polluting and eco-friendly
Solar cells can be used to drive vehicles.
26.
v) The solar cells made of silicon maybe used as source of power in space craft nd
satellites.
What is multification factor and mention its significance?
The number of neutrons resulting from single fission is known as Multiplication factor.
a)
27.
For chain reaction to take place, multification factor should be greater than or equal to
1.
b)
When the multification factor is less than 1, the chain reaction does not take place.
What are the applications of H2 - O2 fuel cell?
(i)
H2-O2 fuel cells are used are used as auxiliary energy resources in space
vehicles, submarines, and other military-vehicles.
(ii)
In the case of H2-O2 fuel cells the product of water is proved to be a valuable
source of fresh water by astronauts.
BATTERIES (STORAGE DEVICES)
28.
What is a battery? Mention the requirements of a battery?
Battery is an arrangement of galvanic cells connected in series. It consists of an anode,
cathode, oxidant and reducing agent. It may be considered as store houses of electrical energy on
demand.
Requirements of a battery:
29.
i)
Battery should be light in weight.
ii)
It voltage should not vary considerably
iii) It should have long life.
What are primary cells and secondary cells?
i)
Primary Batteries (or) Primary cells
In these batteries, electrodes and electrode reaction are cannot be reversed by passing an
external electrical energy. The cell reactions occur only once. The battery has to be discarded after the
exhaustion of their reactants. They are not chargeable. (eg) Dry cell and Mercury cell.
ii)
Secondary Batteries (or) Secondary cells
In these batteries, electrode reaction are can be reversed by passing an external electrical
energy. The batteries can be recharged by passing electric current and used again and again. They
are also called as storage cells (or) accumulators. (eg) Lead acid storeage cell and Nickel cadmium
cell.
30.
List the main advantages of alkaline batteries?
Advantages:
(i) This alkaline battery is called a heavy duty battery because it sustains heavy use and has a
longer shelf life than dry battery.
31.
(ii) It performs better in cold weather than dry battery.
State the reaction when lead storage battery is recharged.
Recharging: The lead storage battery is rechargeable and this is done by applying the
electric current in the opposite direction. Now Pb is deposited on anode and PbO2 is deposited at
cathode. Density of H2SO4 increases.
charging
2 PbSO4 (s) + 2H2O + energy
Pb (s) + PbO2(s)
+ 2H2SO4
Discharging
32.
What are the applications of lead acid battery?
Applications (or) Uses:
(i)
33.
Lead acid battery is used to supply current mainly in automobiles such as cars, buses
etc.
(ii)
It is also used in gas engine ignition, telephone exchanges, hospitals, power stations.
What are the advantages of storage batteries?
Advantages
34.
1. It produces very high current
2. It can be made easily
3. It acts effectively at low temperature
4. The self discharging rate is low
Write the cell representation of NICAD battery.
Ni-Cd battery is also a rechargeable battery. It consists of cadimium anode and NiO2
cathode and an alkaline electrolyte (KOH).Cell representation:
Cd/Cd (OH)2 // KOH(aq)/NiO2/Ni
35.
Write the discharging reactions in lithium ion battery.
The lithium ion battery is recharged by applying the electric current in the opposite direction.
Now Li+ ions come to anode and TiS2 ions come to cathode.
LiTiS2
36.
Li+ +TiS2
What are the advantages and disadvantages of NICAD battery?
Advantages:
i) It has longer life than a lead storage battery.
ii) It is smaller and lighter
Disadvantages
(i) It is more expensive than lead storage battery.
(ii) Cadmium discarded in the environment can enter the human body and cause health
Problems like cardiovascular disease and hypertension
37.
(iii) It also affects the zinc and copper metabolism in the living cells.
(iv) It creates environmental hazard because of its careless disposal by the consumers.
What is the anode and cathode in Nickel cadmium battery?
Ni-Cd battery is also a rechargeable battery. It consists of cadmium anode NiO2 cathode
and an alkaline electrolyte (KOH)
38.
Describe Lithium battery.
Lithium Battery
It is a solid state battery as it uses a solid electrolyte. In this battery, the anode is lithium and the
cathode is made of TiS2. The solid electrolyte used in this is a polymer which permits the passage of
ions but not that of electrons. It is rechargeable.
39.
What are the advantages of using lithium as anode in batteries?
The advantages of using lithium as anode in batteries:
40.
i) Li has the most negative E0 value and therefore generates a higher voltage than the other
types of cells.
ii) The cell voltage is high, 3V
iii) Lithium being a light weight metal, only 7g (1 mole) material is required to produce 1 mole of
electrons.
What are the advantages of Li-S battery?
Advantages:
41.
(i) Lithium sulphur battery has light weight than lead acid battery.
(ii) It has a high energy density.
(iii) It is used in electric cars.
Lithium battery is the cell of future, why?
Lithium battery is the cell of the future – reason
i)
ii)
42.
The cell voltage is high, 3V
Lithium being a light weight metal, only 7 g (1 mole) material is required to produce 1
mole electrons.
iii)
Li has the most negative E0 value and therefore generates a higher voltage than the
other types of cells.
iv)
All the constituents of the battery are solids and therefore are no risk of leakage from the
battery.
v)
This battery can be made in a variety of sizes and shapes.
What are the applications of lithium batteries?
Application:
i)
Astronauts, during their flight in space require water and power supply for the space
craft. Fuel cell simultaneously generates electricity and the water needed for the drinking, washing and
rehydrating dried food in a space craft.
43.
ii)
Fuel cells are used energy source for submarine and military vehicles.
What is a solid state battery? Give one example.
Solid state battery is a battery which uses solid electrolyte instead of liquid or paste electrolyte.
(eg) Lithium battery
44.
Write a short note on alkaline battery.
Alkalaine Battery
Alkaline battery is an improved form of the dry cell. The electrolyte in this cell is potassium
hydroxide (or) sodium hydroxide (an alkali) & hence the name, alkaline battery. Anode consists of zinc
powder, alkaline electrolyte and a gelling material. Cathode consists of MnO 2 carbon and a binder.
They can perform even with a small amount of electrolyte. The cell derives its power from the reduction
of MnO2 cathode & the oxidation of zinc anode.
The cell reactions are
Anode: Zn(s) + 2OH-
Zn(OH)2(S) + 2e-
Cathode: 2MnO2(S) + 2H2O + 2e-
2Mn2O3( S) + 2OH
Overall: Zn(S) + 2MnO2(S) + 2H2O
Zn(OH)2(S) + 2MnO(OH)( S)
The emf of this cell is 1.5V. Zinc anode used in this cell is made porous to provide a large
electrode area. This leads to the delivery of more current unlike when non porous zinc is used.
DETAIL MARKS QUESTION BANK
UNIT - III
NON-CONVENTIONAL ENERGY SOURCES AND STORAGE DEVICES
1. Give any four characteristics of nuclear fission and fusion reaction.
2. What is nuclear reactor? Describe the components of a light – water nuclear power plant with
suitable diagram.
3. State the principle and applications of solar cells (OR) Photogalvanic
4. Write a short note on wind energy.
5. Hint on Alkaline battery with a suitable diagram.
6. Describe the construction and working of H2 - O2 fuel cell.
7. Account on Lead acid battery.
8. Account on NICAD battery. Explain with cell reaction.
9. Explain the construction and working of Lithium battery.
UNIT-IV: ENGINEERING MATERIALS
PART A
1.Define refractories. How can they be classified?
Refractories are materials that can withstand high temperature without softening or deformation
used for the construction of lining in furnaces, kilns, etc. Refractories are classified into 3 types
 Acidic refractories
 Basic refractories
 Neutral refractories
2.
in shape.They are
Give any four characteristics of refractories.
Refractoriess
Refractoriness under load
Thermal spalling
Dimensional stability
are some characteristics of refractories.
3.
What is refractoriness? How is it measured?
Refractoriness is the ability of a material to withstand very high temperature without softening or
deformation under particular service condition. Refractoriness is generally measured as the softening temperature and is
expressed in terms of Pyrometric Cone Equivalent.
4.
What is segar cone test (or) PCE test?
PCE test is conducted by placing the test cone along with segar cone in the electric furnace. The furnace is
heated at a standard rate of 10 °C per minute, during which softening temperature of segar cone and test cone is
determined.
5.
What is RUL test?
RUL test is conducted by applying a constant load of 3.5 or 1.7 5kg/cm2 to the test refractory specimen of
size base 5 cm2 and height 75 cm and hearing in a furnace at a standard rate of 10 ° C per minute
6.
Name the stages in manufacture of refractory?
 Grinding
 Mixing
 Moulding
 Drying
 Firing
Are the stages in manufacture of refractory
7.
What is porosity of a refractory? How can it be modified?
Porosity is defined as the ratio of its pore volume to the bulk volume.
Porosity = W-D/W-A*100
W= Weight of saturated specimen (with water )in air
D=Weight of dry specimen
A=Weight of standard specimen (with water)in water
Porosity of a refractory can be modified by improving its strength, resistance to abrasion and resistance to
corrosion.
8.
What is thermal spalling? How will you control it?
Thermal spalling is the property of breaking, cracking or peeling off a refractory material under high
temperature. It can be controlled by using high porosity, low-coefficient of expansion and good thermal conductivity
refractory.
9.
What are the two types of dimension change?
The dimensional changes are Reversible and Irreversible.
Reversible: This may result due to the uniform expansion and contraction of a refractory.
Irreversible: This may result either in the contraction or expansion of a refractory.
10. What are abrasives?
Abrasives are hard substances used for polishing,shaping,grinding operations.They are characterized by high
melting point, high hardness and chemically inactive.
11. What is abrasive powder?
To clean the surface prior to coating, abrasive powders are used Example: Quartz
and garnet.
12. What is moh’s scale?
Moh’s scale is a scale,in which common abrasives are arranged in the order of their increasing hardness.
Example: Diamond-10,Talc-1
13. How is carborundum prepared?
Silicon carbide is manufactured by heating sand and coke with some sawdust and a little salt in an electric
furnace to about 1500 0 C.
SiO2 + 3CO
SiC + 2CO
14. What is norbide? How can it be prepared?
Norbide is prepared by heating mixture of boron oxide and coke in anm electric furnace to about 2700°C.
2B2O3 + 7C
B4C+6CO
15. Give the applications of garnet and emery.
Garnet is used in making abrasive paper and abrasive cloth and in glass grinding and polishing metals.
Emery is used for grinding pigments in the paint industry and as granules in grinding machines.
16. What are the applications of abrasive?
Abrasives are used in three forms as loose powder, as abrasive cloth, as grinding wheels. Abrasive powder is
used to clean the surface prior to coating.Abrasive is used to prepare smooth wood, metal and plastic surfaces. Grinding
wheels is used for the removal of scales from iron surfaces, cutting tool sharpening.
17. How can we classify the abrasives? Give eg for each type.
Abrasives are classified into two types. Natural Abrasive and Synthetic Abrasive.
Natural Abrasive is further classified into non siliceous and siliceous abrasive.
Example
Non siliceous abrasive: Diamond, Corundum
Siliceous Abrasive: Quartz, Garnet
Synthetic Abrasive: Carborundum,Alundum
18. Define lubricant. Classify them.
into
Lubricant is a substance used in between two moving surfaces to reduce the friction. Lubricant is classified
Liquid
lubricant,
Semi-solid
lubricants,
Solid
lubricants
and
Emulsion.
19. What is flash and fire point.
Flash point is the lowest temperature at which the oil gives off enough vapour that ignite for a moment,
when a small flame is brought near it.
Fire point is the lowest temperature at which the vapour of the oil burns continuously for atleast 5 seconds,
when a small flame is brought near it. Generally the fire point is 5-40 0C higher than flash point.
20. Define viscosity index.
Viscosity index is defined as the average decrease in viscosity of an oil per degree rise in temperature
between 100° F and 210° F.
21. Define cloud and pour point.
When oil is cooled slowly, the temperature at which the oil becomes cloudy in appearance is called its cloud
point.
The temperature at which the oil ceases to flow or pour is called its pour point.
22. What are pour point depressants? Give eg.
Pour point of lubricating oil can be lowered by pour point depressant. Example: Poly alkyl benzene called
‘para flow’ is commonly used pour point depressant.
23. What are greases? How can they be classified?
Greases are semi-solid lubricants obtained by thickening of lubricating oil by the addition of metallic soaps.
Greases are classified into sodium-soap greases, Calcium-soap greases, Barium-soap greases, Lithium-soap greases,
Aluminum-soap greases.
24. What are carbon nanotubes? What are the types?
Carbon nanotubes are allotropes of carbon with a nanostructure having a length-to- diameter ratio greater
than 1,000,000.When graphite sheets are rolled in to a cylinder their edges joined and form carbon nanotubes i.e,carbon
nanotubes are extended tubes of rolled graphite sheets.
25. What are nano materials?
Nanomaterials are the materials having components with size less than 100nm at least in one
dimension.Nanomaterials, in one dimension are layers such as thin films or surface coatings.
Nanomaterials ,in two dimension are tubes such as nanotubes and nanowires.
26. What is nano chemistry?
Nanochemistry is defined as the study of phenomema and manipulation of materials at atomic, molecular
and macromolecular scales.
27. Write down the synthetic methods to prepare carbon nanotubes.
Carbon nanotubes can be synthesized by the following methods.
 Pyrolysis of hydrocarbons
 Laser Evaporation
 Carbon arcmethod
 Chemical Vapour Deposition
28. Write any four applications of carbon nano tube.




Carbon nanotubes play an important role in the battery technology such in fuel cells, Lithium battery.
Carbon nanotubes are used as protective shields.
Carbon nanotubes are also used in sensors of gases.
Carbon naotubes are also used in drug delivery vessels and in microscope.
29. Mention the various forms of SWNT.
Single walled nanotube have various forms such as Armchain structures,Zig-Zag structures and Chiral
nanotubes.
PART-B
1. Classify the refractories. Explain one example for each type.
2. What are the properties of refractory? Explain any three of them.
3. Write notes on alumina, zirconia and magnesite bricks.
4. Write a note on synthetic abrasives.
5. What is your understanding about natural abrasives?
6. How will you explain the mechanism behind the lubrication?
7. Explain any four properties of lubricants?
8. How can you classify lubricants? Explain.
9. Write notes on solid lubricants.
10. Bring out the important applications of CNT.
11. Write a note on structure and synthesis of CNT.
ENGINEERING CHEMISTRY – II
UNIT-V
FUELS AND COMBUSTION
PART-A QUESTIONS
01. What is the significance of ultimate analysis?
02. Why coke is preferred to coal for metallurgical purpose? Or Why is coke superior to coal?
03. Explain the term knocking of a petrol engine?
04. Why should leaded petrol not be used?
05. Define GCV and LCV of a fuel?
06. What is carbonization of coal?
07. Differentiate between thermal cracking and catalytic cracking.
08. What is cetane number? How can it be improved?
09. What is gross calorific value?
10. Define calorific value of a fuel.
11. Compare gasoline oil and diesel oil.
12. Write the advantages of LPG over gaseous fuel.
13. What is power alcohol?
14. What is biodiesel? Mention its advantages.
PART-B QUESTIONS
01. What is metallurgical coke and describe the Otto-Hoffman method of the coke manufacture and the
recovery of various by products.
02. Describe the manufacture of gasoline by Fisher - Tropsch method. OR What is hydrogenation? How is
synthetic petrol manufactured by Fischer Tropsch process?
03. How is synthetic petrol manufactured by Bergius method?
04. What is water gas? How it is manufactured?
05. Calculate the gross net calorific values of coal having the following compositions C = 85%, H = 8%, S =
1%, Ash = 4% latent heat of steam = 587 cal/gm
06. What is producer gas? How it is manufactured?
07. Fuel oil has the following analysis: C = 90%, H = 6%, S = 2.5%, O = 1%, Ash = 0.5%. Calculate the
quantity of air required for combustion of 2 Kg of fuel, if 25% excess air is used.
08. How the fuel gas analysis is carried out? Explain with neat diagram. Write its uses.
11. Give a brief account of refining of petroleum and the products obtained and their uses.
12. Explain the fixed bed catalytic cracking for the manufacture of gasoline.
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