Category: Engineering Chemistry Objective Questions

Engineering Chemistry Multiple Choice Questions on “Liquified Petroleum Gas (LPG)”.

1. At normal ambient temperature and atmospheric pressure, in which form LPG is obtained?
a) Solid
b) Gaseous
c) Liquid
d) Solid-liquid
Answer: b
Clarification: LPG is a certain mixture of light hydrocarbons derived from petroleum. At normal temperature and pressure it is in gaseous state and later on it is condensed to the liquid state by the application of moderate pressure.

2. Under which compound name does the liquid petroleum gas (LPG) are sold?
a) Urea
b) Ethylene
c) Benzoyl peroxide
d) Butane
Answer: d
Clarification: Propane and butane are present in the largest amounts in LPG. Small quantities of ethane, pentane, ethylene and pentene are also present. Under trade names it is represented as HP, Bharat gas and Indian gas in India.

3. By which process only saturated hydrocarbons are obtained in LPG?
a) Straight distillation
b) Thermal Cracking
c) Hydrocracking
d) Reforming
Answer: a
Clarification: The LPG obtained from heavier hydrocarbons by straight distillation process only contains saturated hydrocarbons, where as the LPG obtained from Thermal cracking or hydrocracking contains both saturated and unsaturated hydrocarbons.

4. Which type of LPG is mostly produced in Indian refineries?
a) Grade A
b) Grade B
c) Grade C
d) Grade D
Answer: b
Clarification: According to the Bureau of Indian Standards, grade B contains a mixture of butane and propane. This type of LPG are supplied for domestic uses.

5. According to the Bureau of Indian Standards which type of LPG only contains butane in them?
a) Grade A
b) Grade B
c) Grade C
d) Grade D
Answer: a
Clarification: Grade A consist predominantly of butanes, butylene or mixture of butanes and butylene’s. This type of LPG are most suitable for use due to their moderate rate of combustion.

6. In which regions does the LPG containing propane are found?
a) Hotter region
b) Monsoon region
c) Colder region
d) Terrestrial region
Answer: c
Clarification: LPG containing propane is found in the colder region due to less temperature and pressure conditions. These are found towards the north pole of the earth.

7. Liquid petroleum gas (LPG) is corrosive to steel.
a) True
b) False
Answer: b
Clarification: The sulphur and phosphorous content in LPG are very low due to which these are non-corrosive to steel. This type of fuel is used in industries having large steel supplies.

8. What happens when LPG is inhaled in large concentrations?
a) It kills a person
b) It increases a person’s eye sight
c) It does not have any effect on person’s health
d) It causes a little anaesthesia
Answer: d
Clarification: Butane and propane are present in large amount are LPG. If inhaled in large quantities, it becomes anaesthetic which can cause a person to fall after some time.

9. What is the odour of Liquid Petroleum Gas (LPG)?
a) It is odourless
b) Fruity smell
c) Undesirable odour
d) Alcoholic smell
Answer: a
Clarification: LPG does not have a characteristic odour. Highly odorous compounds such as ethyl and propyl merchants are deliberately mixed so as to help in the detection of any accidental leakage.

10. In which type of industries LPG is used as a fuel?
a) Steel industries
b) Plastic Industries
c) In the production of olefins
d) In the production of coal gas
Answer: c
Clarification: LPG is used as a feedstock for the manufacturing of olefins by the process of pyrolysis. It is also used as a domestic fuel for internal combustion engines.

Engineering Chemistry Multiple Choice Questions on “Hardness of Water”.

1. Hardness of water is due to the presence of salts of ____________
a) Potassium
b) Chlorine
c) Magnesium
d) Boron
Answer: c
Clarification: Hardness of water is due to the presence of salts of calcium and magnesium. Hard drinking water may have moderate health benefits, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water.

2. Select the incorrect statement from the following option.
a) Water which does not form lather with soap and forms white scum is called hard water
b) Hard water contains dissolved calcium and magnesium salts in it
c) In hard water, cleansing quality of soap is depressed
d) Due to the presence of dissolved hardness-producing salts, the boiling point of water is depressed
Answer: d
Clarification: Due to the presence of dissolved hardness-producing salts, the boiling point of water is elevated. Elevation in boiling point is one of the most important colligative property. All the other options are correct.

3. Select the incorrect statement from the following option.
a) Permanent hardness is due to dissolved chlorides and sulphates of calcium and magnesium
b) It can be removed by mere boiling of water
c) It is also known as non-alkaline hardness
d) The difference between the total hardness and the alkaline hardness gives the non-alkaline hardness
Answer: b
Clarification: Unlike temporary hardness, permanent hardness is not destroyed on boiling. Varoius methods are adopted for the removal of permanent hardness like zeolites, lime-soda process etc. All the other options are correct.

4. Alkaline hardness is due to the presence of bicarbonate, carbonate and hydroxides of the hardness-producing metal ions.
a) True
b) False
Answer: a
Clarification: Alkaline hardness is due to the presence of bicarbonate, carbonate and hydroxides of the hardness-producing metal ions. This is also called carbonate hardness. It is temporary and can be removed easily by boiling.

5. Select the incorrect statement from the following option.
a) The taste of hard water is better than soft water
b) The dissolved calcium in hard water can help to produce strong teeth
c) Hard water coats the lead piping with a layer of insoluble calcium carbonate which prevents poisonous lead dissolving in water
d) Boiler feed water should also be hard in nature
Answer: d
Clarification: Boiler feed water should be free from hardness otherwise explosion may occur. All the other options are correct. The taste of hard water is better than soft water and dissolved calcium in hard water can help to produce strong teeth. Hard water coats the lead piping with a layer of insoluble calcium carbonate which prevents poisonous lead dissolving in water.

6. Hardness of water is conventionally expressed in terms of equivalent amount of ____________
a) H₂CO₃
b) MgCO₃
c) CaCO₃
d) Na₂ CO₃
Answer: c
Clarification: Hardness of water is conventionally expressed in terms of equivalent amount of CaCO₃. The total water hardness is the sum of the molar concentrations of Ca²⁺ and Mg²⁺, in mol/L or mmol/L units.

7. The chemical equivalent of MgSO₄ salt is ____________
a) 60
b) 47.5
c) 82
d) 68
Answer: a
Clarification: The molar mass of MgSO₄ is 120 and its n-factor is 2. So, chemical equivalent = Molar mass/ n-factor = 60.

8. Which of the following is not a unit of hardness?
a) Parts per million
b) Degree centigrade
c) Degree clarke
d) Degree French
Answer: b
Clarification: Degree centigrade is not a unit of hardness. Degree centigrade is the unit of temperature. The unit for hardness is ppm (parts per million), degree clarke and degree french. All these three units are inter-related.

9. 1 degree Clarke = 1 part of CaCO₃ per _____________ parts of water.
a) 10,000
b) 30,000
c) 50,000
d) 70,000
Answer: d
Clarification: 1 degree Clarke = 1 part of CaCO₃ per 70,000 parts of water. It is calculated mathematically.

10. 1 ppm = ____________
a) 0.07 ⁰Fr
b) 0.7⁰Fr
c) 0.1⁰Fr
d) 0.01⁰Fr
Answer: c
Clarification: 1 ppm = 0.1⁰Fr. It is calculated mathematically.

11. How many grams of MgCO₃ dissolved per litre gives 84 ppm hardness?
a) 70.56 mg/L
b) 48.23 mg/L
c) 81.49mg/L
d) 66.12 mg/L
Answer: a
Clarification: 70.56 mg/L of MgCO₃ dissolved per litre gives 84 ppm hardness.

12. EDTA method for hardness determination is a less accurate and inconvenient procedure.
a) True
b) False
Answer: b
Clarification: EDTA method for hardness determination is a more accurate, convenient and rapid procedure. Ethylene diaminetetraacetic acid (EDTA), is an amino poly-carboxylic acid and a colorless, water-soluble solid.

Engineering Chemistry Multiple Choice Questions on “Electroplating Baths – 1”.

1. Identify the electrolyte in sodium arsenide plating.
a) Arsenide solution
b) Arsenide salt solution
c) Arsenide metal
d) Salt solution
Answer: b
Clarification: During the process of electroplating, impure metal is kept as anode and pure metal is kept as a cathode. Also for the diffusion of ions to take place, an electrolytic solution is needed which is nothing but metal salt solution (that is arsenide salt solution).

2. Identify the electrolyte in chromium deposition.
a) Potassium chromate solution
b) Red chromate
c) Chromium sulphide
d) Yellow chromate
Answer: a
Clarification: Since from the above four options, charge carriers diffuse more rapidly through potassium chromate solution (though all the four solutions can be electrolytes). The reason is potassium chromate is alkaline is nature and allows the free flow of electrons.

3. What is anode mud?
a) Impurity found below anode after plating
b) Impurity which can separated from the mixture using filtration
c) Impurity which cannot be separated
d) Distilled impurity
Answer: a
Clarification: During electroplating of noble materials, some electrons may shift toward the pure materials resulting in the deposition of its ore components. Usually, anode muds are basically noble metals like zinc, silver etc.

4. How can anode mud be removed?
a) Filtration
b) Distillation
c) Sublimation
d) Decomposition
Answer: a
Clarification: Since anode mud is nothing but noble metals, they do not mix with the electrolyte (they form heterogeneous solution with them). Hence they can be removed easily by using the process called filtration.

5. Can a non-metal be used as an electrolyte?
a) No because they form immiscibility with the main material
b) Yes because they have high discharge capacity
c) No because they are poor conductors of electricity
d) Yes because they have retentivity
Answer: c
Clarification: Since the main principle of electroplating is a passage of current, only metal electrolytes will have the ability to make charges flow and hence non-metals cannot be used.

6. Identify the anode mud in the separation of gold from its ore.
a) Copper
b) Zinc
c) Silver
d) Silver and Zinc
Answer: d
Clarification: Since the ore of gold contains other noble materials like tin, aluminium, magnesium etc, the most commonly and abundantly available materials are only zinc and silver (65 and 43% respectively).

7. Identify the type of electrolyte: NaCl, acetic acid.
a) Strong, Weak
b) Weak, Strong
c) Strong, Strong
d) Weak, Weak
Answer: a
Clarification: Since NaCl dissociates completely in water (that is it gives the correct proportion of H+ and OH-
ions respectively) whereas acetic acid fails to do so. Hence they are strong and weak electrolytes respectively.

8. Identify the strong electrolytes from the following.
a) NaCl, CaCl
b) Acetic acid, CaCl
c) CaCl, citric acid
d) Chromate
Answer: a
Clarification: Since NaCl and CaCl dissociates completely in water (that is it gives the correct proportion of H+ and OH- ions respectively) whereas acetic acid fails to do so. Hence NaCl and CaCl are strong electrolytes.

9. What is the life span of a general metal electrolyte?
a) 1 hour
b) 2 hours
c) 3 hours
d) 5 hours
Answer: c
Clarification: After the process of electroplating, the electrolyte can stay up to a time period of 3 hours and then it would decay automatically. This process of decay of electrolyte is called decomposition.

10. Who discovered electroplating?
a) Luigi Brugnatelli
b) Thomas Kennedy
c) Johansen Mathews
d) Mariana Simsons
Answer: a
Clarification: Luigi Brugnatelli got the idea of electroplating in the late 80’s when he first discovered that metals can transform electricity from one form to another within themselves. This idea led to the evolution of electroplating.

Engineering Chemistry Multiple Choice Questions on “Engineering Materials”.

1. Based on the important category, concrete and fibre glass are the examples of ___________
a) Ceramics
b) Polymers
c) Composites
d) Semi-conductors
Answer: c
Clarification: Example of ceramic are Al₂O₃ and ZrO₂, Polymers are Thermoplastic and Thermosets, Composites are Fibre glass and Concrete and Semi-conductors are Silicon and Germanium.

2. Which of the following is not an inorganic functional material?
a) Ferroelectric
b) Reverse micelles
c) Magnetic field sensor
d) Light detectors
Answer: b
Clarification: Reverse micelles is an organic functional material.

3. Which of the following is not an aerospace material?
a) Plastics
b) Silica
c) Aluminium alloys
d) Polymers
Answer: d
Clarification: Polymers are not categorized under aerospace materials.

4. Select the incorrect statement from the following option.
a) Metals are extremely good conductors of heat and electricity
b) The properties of metal degrade rapidly with temperature
c) Metals have poor corrosion resistant
d) A polished metal surface has a dull appearance
Answer: d
Clarification: A polished metal surface has a lustrous appearance. All the other options are correct. Metals are extremely good conductors of heat and electricity, its properties degrade rapidly with temperature and have poor corrosion resistance.

5. Which one of the following is the best heat and corrosion resistant material?
a) Metals
b) Ceramics
c) Polymers
d) Semi-conductors
Answer: b
Clarification: Ceramics materials generally consist of oxides, nitrides, carbides, silicates or borides of various metals. Their heat and corrosion resistance is best compared to metals and polymers.

6. Polymers are used in the chemical industry because of their ___________
a) Inert nature
b) Light weight
c) Low cost
d) Easiness in fabricability
Answer: a
Clarification: Polymers are used in the chemical industry because of their inert nature.

7. Select the incorrect statement from the following option.
a) Composites are optically opaque materials
b) Carbon fiber reinforced composite materials are not used in space vehicles
c) Re-cyclability of composite material is poor
d) Processing of composite material is difficult
Answer: b
Clarification: Carbon fiber reinforced composite materials are used in space vehicles. All the other options are correct. Composites are optically opaque materials, re-cyclability of composite material is poor and its processing is difficult.

8. Which type of material expands and contract in response to an applied electric field?
a) Advanced material
b) Smart material
c) Biomaterial
d) Nanomaterial
Answer: b
Clarification: Smart materials(Piezoelectric) expand and contract in response to an applied electric field(or voltage).

9. Which one of the following is non-linear material?
a) Zirconium oxide
b) Magnetite
c) Maghemite
d) Lithium niobate
Answer: d
Clarification: Lithium niobate is a non-linear material used for telecommunication.

10. Which of the following is not an application of nanomaterials?
a) TV and computer monitors
b) Cardiology
c) Magnetic Resonance Imaging (MRI)
d) Sunscreens and fuel cells
Answer: b
Clarification: Cardiology is not an application of nanomaterials. TV and computer monitors, Magnetic Resonance Imaging (MRI) and sunscreens and fuel cells are some of the applications of nanomaterials.

Engineering Chemistry Multiple Choice Questions on “Carbocations”.

1. Stability of free radicals can be explained on the basis of __________
a) Inductive effect
b) Electromeric effect
c) Hyperconjugation
d) Mesomeric effect
Answer: c
Clarification: Stability of free radicals can be explained on the basis of hyperconjugation effect and ease of formation.

2. The hybridisation of carbocation is __________
a) Sp
b) Sp²
c) Sp³
d) Sp³d
Answer: b
Clarification: The hybridisation of carbocation is sp². A carbocation is molecule in which a carbon atom bears three bonds and a positive charge.

3. Arrange the following carbocations in the order of increasing stability.
a) Benzyl > 3⁰ > 2⁰ > 1⁰
b) Benzyl > 1⁰ > 2⁰ > 3⁰
c) 3⁰ > 2⁰ > 1⁰ > Benzyl
d) 1⁰ > 2⁰ > 3⁰ > Benzyl
Answer: a
Clarification: The correct stability order of carbocation is- Benzyl > 3⁰ > 2⁰ > 1⁰. Benzyl carbocation is the most stable and 1⁰ carbocation is least stable.

4. The shape of carbocation is __________
a) Pyramidal
b) Bent
c) Linear
d) Trigonal planar
Answer: d
Clarification: The shape of the carbocation is a trigonal planar. It is sp² hybridised. A carbocation is molecule in which a carbon atom bears three bonds and a positive charge.

5. Carbonium ions are the intermediates in which the positive charge is carried by the carbon atom with ___________ electrons in the valence shell.
a) 6
b) 5
c) 4
d) 3
Answer: a
Clarification: Carbonium ions are the intermediates in which the positive charge is carried by the carbon atom with six electrons in the valence shell. It is an organic cation in which the positive charge is located on a carbon atom.

6. Positive charge of carbocations can be dispersed by __________
a) (+I) effect of alkyl group
b) Resonance in allyl or benzyl carbocation
c) Hyperconjugation in 1⁰, 2⁰ and 3⁰ carbocations
d) All of the mentioned
Answer: d
Clarification: Positive charge of carbocations can be dispersed by (+I) effect of alkyl group or by resonance in allyl or benzyl carbocation or by hyperconjugation in 1⁰, 2⁰ and 3⁰ carbocations.

7. Alkyl substitution at the carbon bearing positive charge stabilizes carbocations.
a) True
b) False
Answer: a
Clarification: Alkyl substitution at the carbon bearing positive charge stabilizes carbocations. Carbocation is a molecule in which a carbon atom bears three bonds and a positive charge.

8. The formal charge at the carbocation is equal to __________
a) -1
b) 0
c) +1
d) +2
Answer: c
Clarification: The formal charge at the carbocation is equal to +1. A carbocation is molecule in which a carbon atom bears three bonds and a positive charge.

9. The homolytic bond dissociation energy is inversely proportional to the __________
a) Bond length
b) Ease of formation
c) Dipole moment
d) All of the mentioned
Answer: b
Clarification: The homolytic bond dissociation energy is inversely proportional to the ease of formation of free radicals. Free radicals do not carry any charge.

10. Which of the following free radical has the maximum ease of formation?
a) 1⁰
b) 2⁰
c) 3⁰
d) CH₃
Answer: c
Clarification: 3⁰ free radical has the maximum ease of formation. Free radicals do not carry any charge.