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Multiple choice question for engineering

Set 1

1. Water is mainly used in boilers for the generation of
a) Power
b) Electricity
c) Steam
d) Current

View Answer

Answer: c [Reason:] Water is mainly used in boilers for the generation of steam. This steam is further used in the power plants for the generation of electricity.

2. Which of the following should not be a composition of boiler-feed water?
a) Hardness should be below 0.2ppm
b) Its caustic alkalinity should lie between 0.15 to 0.45 ppm
c) Its soda alkalinity should be 0.45-1 ppm
d) Its caustic alkalinity should be 1.5-2 ppm

View Answer

Answer: d [Reason:] Its caustic alkalinity should be 0.15-0.45 ppm. All the other options are correct. Hardness should be below 0.2ppm, caustic alkalinity should lie between 0.15 to 0.45 ppm and soda alkalinity should be 0.45-1 ppm.

3. Which of the following is not a result of excess of impurity in boiler-feed?
a) Scale and sludge formation
b) Decomposition
c) Corrosion, priming and foaming
d) Caustic embrittlement

View Answer

Answer: b [Reason:] Excess of impurities in boiler-feed results in sacle and sludge formation, corrosion, priming,foaming and caustic embrittlement. It does not contribute to decomposition process.

4. If the precipitate formed is soft, loose and slimy, these are __________ and if the precipitate is hard and adhering on the inner wall, it is called _____________.
a) Sludges, scale
b) Scale, sludges
c) Sludges, rodent
d) Scale, rodent

View Answer

Answer: a [Reason:] If the precipitate formed is soft, loose and slimy, these are sludges and if the precipitate is hard and adhering on the inner wall, it is called scale. A rodent is a small furry mammal whose teeth never stop growing.

5. Which of the following option is incorrect about the sludges?
a) Sludges are soft, loose and slimy precipitate
b) They are non-adherent deposits and can be easily removed
c) Formed generally at heated portions of the boiler
d) Can be removed by blow down operation

View Answer

Answer: c [Reason:] Sludges are formed generally at colder portions of the boiler. All the other options are correct. Sludges are soft, loose and slimy precipitate, non-adherent deposits and can be easily removed by blow down operation.

6. State true or false. The scales decrease the efficiency of boiler and chances of explosions are also there.
a) True
b) False

View Answer

Answer: a [Reason:] The scales decrease the efficiency of boiler and chances of explosions are also there. Scale is the precipitate which is hard and adhering on the inner wall.

7. The propulsion of water into steam drum by extremely rapid, almost explosive boiling of water at the heating surface is called
a) Foaming
b) Priming
c) Corrosion
d) Caustic embrittlement

View Answer

Answer: b [Reason:] The propulsion of water into steam drum by extremely rapid, almost explosive boiling of water at the heating surface is called priming. Priming is necessary as it removes all the air voids from the passage of water.

8. The phenomenon during which the boiler material becomes brittle due to accumulation of caustic substances is known as
a) Foaming
b) Priming
c) Corrosion
d) Caustic embrittlement

View Answer

Answer: d [Reason:] The phenomenon during which the boiler material becomes brittle due to accumulation of caustic substances is known as caustic embrittlement. This can be prevented by using sodium phosphate instead of sodium carbonate as softening reagents.

9. Foaming is caused by the formation of
a) Acids
b) Alcohols
c) Oils and alkalis
d) Ketones

View Answer

Answer: c [Reason:] Foaming is caused by the formation of oils and alkalis. Oils and Alkalis becomes sticky and greasy on the surface and hence results in foaming.

10. State true or false. Corrosion is the decay or disintegration of boiler body material either due to chemical or electrochemical reaction with environment.
a) True
b) False

View Answer

Answer: a [Reason:] Corrosion is the decay or disintegration of boiler body material either due to chemical or electrochemical reaction with environment. It converts a refined metal to a more stable form, such as its oxide, hydroxide, or sulphide.

Set 2

1. On increasing the temperature of a liquid, its vapour pressure
a) Decreases
b) Remain constant
c) Increases
d) None of the mentioned

View Answer

Answer: c [Reason:] The vapour pressure of a liquid increases with increase in temperature. Vapour pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature in a closed system.

2. The boiling point of a liquid is the temperature at which the vapour pressure
a) Is equal to internal pressure
b) Is equal to external pressure
c) Is greater than internal pressure
d) Is lesser than internal pressure

View Answer

Answer: b [Reason:] The boiling point of a liquid is the temperature at which the vapour pressure is equal to external pressure. The boiling point of a liquid varies depending upon the surrounding environmental pressure.

3. The normal boiling point of a liquid is the temperature at which it boils when the external pressure is
a) 1 atm
b) 2 atm
c) 3 atm
d) 5 atm

View Answer

Answer: a [Reason:] The normal boiling point of a liquid is the temperature at which it boils when the external pressure is 1 atm. The boiling point of a liquid varies depending upon the surrounding environmental pressure.

4. If the non-volatile impurities contaminate the liquid, its boiling point gets
a) Depressed
b) Elevated
c) Remains same
d) None of the mentioned

View Answer

Answer: b [Reason:] If the non-volatile impurities contaminate the liquid, its boiling point gets elevated. This is one of the most important colligative property. Example: salt water boils at a higher temperature than pure water.

5. The energy required to vaporize 1 mole of a liquid is known as
a) Molar heat of fusion
b) Molar heat of freezing
c) Molar heat of boiling
d) Molar heat of vaporisation

View Answer

Answer: d [Reason:] The energy required to vaporize 1 mole of a liquid is known as molar heat of vaporisation. It is the amount of heat necessary to boil (or condense) one mole of a substance at its boiling point.

6. At 1 atm pressure, the boiling point of water is
a) 0 0C
b) 1000C
c) -1000C
d) None of the mentioned

View Answer

Answer: b [Reason:] The boiling point of water at 1 atm pressure is 1000C. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure.

7. The boiling point and molar heat of vaporisation is dependent on
a) Strength of the inter-molecular forces
b) Composition of the liquid compound
c) Size of the molecules
d) All of the mentioned

View Answer

Answer: a [Reason:] The boiling point and molar heat of vaporisation is dependent on the strength of the inter-molecular forces. The boiling point of a liquid varies depending upon the surrounding environmental pressure.

8. Select the incorrect statement from the following options.
a) Methane and argon have weak dispersion forces so their boiling point is low
b) Diethyl ether has a dipole moment, and the dipole-dipole forces accounts for its moderately high boiling point
c) Water and ethanol have strong hydrogen bonding and hence they possess high boiling point
d) Mercury has weak metallic bonding which is responsible for its low boiling point

View Answer

Answer: d [Reason:] Mercury has strong metallic bonding which is responsible for its high boiling point. All the other options are correct. Methane and argon have weak dispersion forces so their boiling point is low. Diethyl ether has a dipole moment, and the dipole-dipole forces accounts for its moderately high boiling point. Water and ethanol have strong hydrogen bonding and hence they possess high boiling point.

9. For a given substance, choose the correct statement.
a) ΔHfus is greater than ΔHvap
b) ΔHfus is equal to ΔHvap
c) ΔHfus is smaller than ΔHvap
d) None of the mentioned

View Answer

Answer: c [Reason:] For a given substance, ΔHfus is smaller than ΔHvap.

10. The molar heat of vaporisation (ΔHvap) for water is
a) 40.79 kJ/mol
b) 31.0 kJ/mol
c) 59.0 kJ/mol
d) 9.2 kJ/mol

View Answer

Answer: a [Reason:] The molar heat of vaporisation (ΔHvap) for water is 40.79 kJ/mol. Vapor pressures and boiling points of substances can be affected by the presence of dissolved impurities (solutes) or other miscible compounds, the degree of effect depending on the concentration of the impurities or other compounds.

Set 3

1. Select the correct statement from the following option.
a) Carbanion is the intermediate compound
b) In carbanion, central carbon atom carries negative charge
c) It possess unshared pair of electron
d) All of the mentioned

View Answer

Answer: d [Reason:] Carbanion is the intermediate compound in which central carbon atom carries negative charge and it possess unshared pair of electron. It is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons.

2. The hybridisation of carbanion is
a) Sp
b) Sp2
c) Sp3
d) Sp3d

View Answer

Answer: c [Reason:] The hybridisation of carbanion is sp3. A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons.

3. The formal charge at the carbanion is
a) +1
b) -1
c) 0
d) +2

View Answer

Answer: b [Reason:] The formal charge at the carbanion is -1. A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons.

4. The geometry of carbanion is
a) Pyramidal
b) Linear
c) Tetrahedral
d) Trigonal planar

View Answer

Answer: a [Reason:] The geometry of carbanion is pyramidal. A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons.

5. State true or false. The structure of carbanion is pyramidal but it undergoes rapid inversion similar to those of amines.
a) True
b) False

View Answer

Answer: a [Reason:] The structure of carbanion is pyramidal but it undergoes rapid inversion similar to those of amines. The carbanion exists in a trigonal pyramidal geometry. Formally, a carbanion is the conjugate base of a carbon acid.

6. Negative charge of carbanion can be dispersed by
a) (+I) effect and resonance
b) (-I) effect and resonance
c) Hyperconjugation
d) (+M) effect and resonance

View Answer

Answer: b [Reason:] Negative charge of carbanion can be dispersed by (+I) effect and resonance. A carbanion is a nucleophile. The stability and reactivity of a carbanion is determined by several factors.

7. Which of the following carbanion is least stable?
a) 10
b) 20
c) 30
d) CH3

View Answer

Answer: c [Reason:] 30 carbanion is the least stable carbanion. The same factors that determine the stability of the carbanion also determine the order in pKa in carbon acids.

8. Which of the following carbanion is most stable?
a) 10
b) 20
c) 30
d) CH3

View Answer

Answer: d [Reason:] CH3 carbanion is the most stable carbanion. The same factors that determine the stability of the carbanion also determine the order in pKa in carbon acids.

9. On increasing the number of alkyl groups, the stability of carbanions
a) Increases
b) Decreases
c) Remains same
d) None of the mentioned

View Answer

Answer: b [Reason:] On increasing the number of alkyl groups, the stability of carbanions decreases. The alkyl groups have (-I) effect.

10. State true of false. Due to (+I) effect, the methyl groups are electron accepting in nature.
a) True
b) False

View Answer

Answer: b [Reason:] Due to (+I) effect, the methyl groups are electron releasing in nature. The same factors that determine the stability of the carbanion also determine the order in pKa in carbon acids.

Set 4

1. Stability of free radicals can be explained on the basis of
a) Inductive effect
b) Electromeric effect
c) Hyperconjugation
d) Mesomeric effect

View Answer

Answer: c [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: d [Reason:] The shape of carbocation is 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: d [Reason:] 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. State true or false. Alkyl substitution at the carbon bearing positive charge stabilizes carbocations.
a) True
b) False

View Answer

Answer: a [Reason:] Alkyl substitution at the carbon bearing positive charge stabilizes carbocations. Carbocation is 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

View Answer

Answer: c [Reason:] 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 propotional to the
a) Bond length
b) Ease of formation
c) Dipole moment
d) All of the mentioned

View Answer

Answer: b [Reason:] The homolytic bond dissociation energy is inversely propotional 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

View Answer

Answer: c [Reason:] 30 free radical has the maximum ease of formation. Free radicals do not carry any charge.

Set 5

1. Which of the following is not a category of catalysis?
a) Homogeneous
b) Heterogeneous
c) Artificial
d) Enzymatic

View Answer

Answer: c [Reason:] The four categories of catalysis are: homogeneous, heterogeneous, auto and enzymatic. Artificial is not a category of catalysis.

2. Which of the following is an example of homogeneous catalysis?
a) Enzyme catalysis
b) Hardening of animal and vegetable oils
c) Haber’s process
d) Cracking of heavy oils for synthesis of gasoline

View Answer

Answer: a [Reason:] Enzyme catalysis is an example of homogeneous catalysis. All the other options are not examples of homogeneous catalysis.

3. Which of the following act as catalysis for Williamson’s etherification process?
a) HCl
b) NaCl
c) KMnO4
d) H2SO4

View Answer

Answer: d [Reason:] H2SO4 act as catalysis for Williamson’s etherification process. The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and an a deprotonated alcohol.

4. Select the incorrect statement from the following option.
a) Intermediate compound formation theory fails to explain the action of promoters
b) Intermediate compound formation theory fails to explain the function of catalyst in homogeneous reactions
c) Intermediate compound formation theory fails to explain the action of catalytic poisons
d) Intermediate compound formation theory fails to explain the function of catalyst in heterogeneous reactions

View Answer

Answer: b [Reason:] Intermediate compound formation theory explains the function of catalyst in homogeneous reactions. All the other options are correct. But it fails to explain the action of promoters, action of catalytic poisons and function of catalyst in heterogeneous reactions.

5. Select the incorrect statement about the adsorption theory from the following option.
a) The surface of the solid catalyst possess some isolated active centres having residual affinity
b) Due to these centres, the molecules of the gaseous reactants get adsorbed in unimolecular thick layer
c) The adsorbed reactants get activated and then react
d) The energy required for activation is more than that required for uncatalysed reaction

View Answer

Answer: d [Reason:] The energy required for activation is less than that required for uncatalysed reaction, and hence the reaction goes faster. All the other options are correct.

6. State true or false. No definite intermediate compound formation takes place in contact theory.
a) True
b) False

View Answer

Answer: a [Reason:] No definite intermediate compound formation takes place in contact theory. The contact hypothesis has been described as one of the best ways to improve relations among groups that are experiencing conflict.

7. Which of the following step is rate determining step of contact theory?
a) Diffusion of reactants to surface
b) Adsorption of reactants at the surface
c) Chemical reaction at the surface
d) Desorption of products from the surface

View Answer

Answer: c [Reason:] Chemical reaction at the surface is the slowest and rate determining step of contact theory. The contact hypothesis has been described as one of the best ways to improve relations among groups that are experiencing conflict.

8. Which of the following statement is incorrect about the adsorption theory?
a) The catalyst is more efficient in finely divided state
b) Action of promoters is not explained
c) Enhanced activity of a rough surfaced catalyst is explained
d) Specific action of catalyst is explained

View Answer

Answer: b [Reason:] Action of promoters and catalytic poisons is also explained. All the other options are correct. The catalyst is more efficient in finely divided state.

9. The factor which determine the activity of a heterogeneous catalyst is
a) Total surface area only
b) The number of active sites per unit amount of catalyst only
c) Method of preparation, prior treatment only
d) Total surface area, number of active sites and method of preparation

View Answer

Answer: d [Reason:] The factors which determine the activity of a heterogeneous catalyst are – Total surface area, the number of active sites per unit amount of catalyst and method of preparation, prior treatment.

10. What is the optimum temperature for Haber’s process?
a) 4500C
b) 450C
c) 1500C
d) 3000C

View Answer

Answer: a [Reason:] The optimum temperature for Haber’s process is 4500C. Haber’s process is an industrial process for producing ammonia from nitrogen and hydrogen, using an iron catalyst at high temperature and pressure.

11. Which of the following process is used for the manufacturing of acetic acid?
a) Bosch’s process
b) Deacon’s process
c) Vinegar process
d) Chamber process

View Answer

Answer: c [Reason:] Vinegar process is used for the manufacturing of acetic acid. The term “vinegar” actually refers to the two-step process of fermentation from a carbohydrate to an alcohol to an acetic acid.

12. Which of the following process is used for the preparation of sulphuric acid?
a) Ostwald’s process
b) Bergius process
c) Deacon’s process
d) Chamber process

View Answer

Answer: d [Reason:] Chamber process is used for the preparation of sulphuric acid. Chamber process, also called Lead-chamber Process, method of producing sulfuric acid by oxidizing sulfur dioxide with moist air, using gaseous nitrogen.