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Multiple choice question for engineering

Set 1

1. Which of the following is rate determining step in electrophilic substitution reaction?
a) Generation of electrophile
b) Attack by an electrophilic reagent on benzene ring
c) Formation of product
d) All of the mentioned

View Answer

Answer: b [Reason:] Attack by an electrophilic reagent on benzene ring is a rate determining step in electrophilic substitution reaction. It is also the slowest step of the reaction.

2. Which of the following act as a catalysis in the nitration of benzene?
a) Conc. HCl
b) Dil. HCl
c) Conc. H2SO4
d) Dil. H2SO4

View Answer

Answer: c [Reason:] Conc. H2SO4 act as a catalysis in the nitration of benzene. Benzene is treated with a mixture of concentrated nitric acid and concentrated sulphuric acid at a temperature not exceeding 50°C.

3. Fuming sulphuric acid is the solution of _________% SO3 in conc. H2SO4.
a) 10
b) 9
c) 8
d) 7

View Answer

Answer: d [Reason:] Fuming sulphuric acid is the solution of 7% SO3 in conc. H2SO4. It is also called Oleum which is produced in the contact process, where sulphur is oxidized to sulphur trioxide which is subsequently dissolved in concentrated sulphuric acid.

4. Which of the following is the necessary condition for desulphonation?
a) Remove volatile hydrocarbon by steam distillation
b) Low concentration of water
c) High concentration of sulphonating agent
d) A large excess of fuming sulphuric acid

View Answer

Answer: a [Reason:] The necessary condition for desulphonation is- Use dilute acid, high concentration of water and remove volatile hydrocarbon by steam distillation.

5. Which of the following act as electrophile in halogenation?
a) Nitronium ion
b) Sulphonium ion
c) Halonium ion
d) Acylium ion

View Answer

Answer: c [Reason:] Halonium ion act as electrophile in halogenation. Nitronium ion is used in nitration. Sulphonium ion is used in sulphonation. Acylium ion is used in acylation.

6. Aromatic bromination catalyzed by the Lewis acid thalium acetate gives
a) Para isomer
b) Ortho isomer
c) Meta isomer
d) Para and ortho isomer

View Answer

Answer: a [Reason:] Aromatic bromination catalyzed by the Lewis acid thalium acetate gives only para isomer. It is not Ortho and meta directing.

7. The reaction in which benzene reacts with alkyl halide in presence of a lewis acid as catalyst to produce alkylbenzene is known as
a) Nitration
b) Halogenation
c) Friedel-Crafts Acylation
d) Friedel-Crafts Alkylation

View Answer

Answer: d [Reason:] The reaction in which benzene reacts with alkyl halide in presence of a lewis acid as catalyst to produce alkylbenzene is known as Friedel-Crafts Alkylation. With anhydrous ferric chloride as a catalyst, the alkyl group attaches at the former site of the chloride ion.

8. Which of the following is not a product of reaction of benzene with CH3Cl and AlCl3?
a) Toulene
b) Isopropyl benzene
c) O-xylene
d) P-xylene

View Answer

Answer: b [Reason:] p-xylene is not a product of reaction of benzene with CH3Cl and AlCl3. Toulene, isopropyl benzene and O-xylene are the products of such reaction.

9. The product of Friedel-Crafts Acylation reactions are
a) Alkylbenzene
b) Alkylamine
c) Arylketone
d) Halobenzene

View Answer

Answer: c [Reason:] The product of Friedel-Crafts Acylation reactions are Arylketone. The acylated products may easily be converted to the corresponding alkanes via Clemmensen Reduction or Wolff-Kishner Reduction.

10. How will you convert benzene into n-propyl benzene?
a) Friedel-Crafts Alkylation
b) Friedel-Crafts Acylation
c) Friedel-Crafts Alkylation followed by clemmensen reduction
d) Friedel-Crafts Acylation followed by clemmensen reduction

View Answer

Answer: d [Reason:] Friedel-Crafts Acylation followed by clemmensen reduction of ketone will give n-propyl benzene. Clemmensen reduction is a chemical reaction described as a reduction of ketones (or aldehydes) to alkanes using zinc amalgam and hydrochloric acid.

Set 2

1. Based on important category, concrete and fibre glass are the examples of
a) Ceramics
b) Polymers
c) Composites
d) Semi-conductors

View Answer

Answer: c [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: b [Reason:] Ceramics materials generally consists 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 chemical industry because of their
a) Inert nature
b) Light weight
c) Low cost
d) Easiness in fabricability

View Answer

Answer: a [Reason:] Polymers are used in 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

View Answer

Answer: b [Reason:] 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 expand and contract in response to an applied electric field?
a) Advanced material
b) Smart material
c) Biomaterial
d) Nanomaterial

View Answer

Answer: b [Reason:] 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

View Answer

Answer: d [Reason:] Lithium niobate is 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

View Answer

Answer: b [Reason:] 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.

Set 3

1. What are Stereoisomer?
a) Isomers having same molecular formula and same configuration
b) Isomers having same molecular formula but different configuration
c) Isomers having different molecular formula but same configuration
d) Isomers having different molecular formula and different configuration

View Answer

Answer: b [Reason:] Stereoisomerism is exhibited by isomers having same molecular formula but different configuration.

2. What are diastereomers?
a) Molecules with non-superimposable mirror images
b) Molecules with superimposable mirror images
c) Molecules which do not have non-superimposable mirror images
d) None of the mentioned

View Answer

Answer: c [Reason:] Diastereomers are those stereomers which do not have non-superimposable mirror images.

3. Which type of compounds cannot exhibit geometrical isomerism?
a) Singly Bonded
b) Doubly Bonded
c) Triply Bonded
d) Cyclic Compounds

View Answer

Answer: c [Reason:] Triply bonded compounds cannot exhibit geometrical isomerism as the -C=C- bond in these molecule is linear.

4. Choose the correct option from the following.
a) A group gets priority if its atomic number is high
b) When atoms attached to a double bond have same atomic number, the first atoms are considered
c) A group gets priority if its atomic number is low
d) Lone pair gets more priority and is ranked above hydrogen

View Answer

Answer: a [Reason:] A group gets priority if its atomic number is high and When atoms attached to a double bond have same atomic number, the second atoms are considered.

5. In which type of projection we can get staggered and eclipsed conformations?
a) Newman Projection
b) Sawhorse Projection
c) Fischer Projection
d) Wedge Projection

View Answer

Answer: b [Reason:] A sawhorse projection can reveal staggered and eclipsed conformations.

6. Assign E or Z configuration to the given compound.
EZ-nomenclature
a) E-configuration
b) Z-configuration
c) S-configuration
d) R-configuration

View Answer

Answer: a [Reason:] Trans-2-butene has two geometric isomers and this is E-configuration.

7. Which of the following compounds have Z-configuration?
a) CH3CH3CH2>C=C<HCH3
b) HPh>C=C<COOHPh
c) H2NCl>C=C<COOHBr
d) CH3Ph>C=C<CH2CH3Br

View Answer

Answer: b [Reason:] All the other options are in E-configuration. Only the second option shows the Z-configuration.

8. Select the incorrect option from the following.
a) Fischer projections are two dimensional representations of three dimensional molecules
b) A molecule is achiral if it cannot be superimposed on its mirror reflection
c) E and Z notations are based on Cahn, Ingold and Prelog priority system
d) Chiral molecules which are non-superimposable mirror images of each other are enantiomers

View Answer

Answer: b [Reason:] A molecule is achiral if it is superimposable on its mirror reflection. All the other options are correct.

9. The cis-trans nomenclature is not applicable when
a) The different groups attached to the carbon atom of double bond are same
b) Atleast one of the group attached to each carbon atom is same
c) The different groups attached to the carbon atom of double bond are not same
d) The cis-trans nomenclature is applicable for all compounds

View Answer

Answer: c [Reason:] The cis-trans nomenclature is applicable when the different groups attached to the carbon atom of double bond are same or atleast one of the group attached to each carbon atom is same.

10. In glyceraldehydes, the complete sequence of priority is
a) –OH > -CH2OH > -CHO > -H
b) –H > -CH2OH > -CHO > -OH
c) –H > –OH > -CH2OH > -CHO
d) –OH > CHO > -CH2OH > -H

View Answer

Answer: d [Reason:] In glyceraldehydes, the complete sequence of priority is –OH > CHO > -CH2OH > -H.

Set 4

1. According to Faraday’s first law of electrolysis, the amount of any substance deposited at the electrode is directly proportional to the quantity of
a) Voltage drop
b) Resistance
c) Electricity passed
d) Tolerance

View Answer

Answer: c [Reason:] According to Faraday’s law of electrolysis, the amount of any substance deposited at the electrode is directly proportional to the quantity of electricity passed. It is given by: m = ( Q / F ) * ( M / Z ) where, m = Mass of the substance liberated at an electrode in grams Q = Total electric charge passed through the substance in Coulombs F = Faraday constant M = Molar mass of the substance in grams per mol Z = Valency number of ions of the substance For Faraday’s first law, M, F, and z are constants, so that the larger the value of Q the larger m will be.

2. Electrochemical equivalent may be defined as the ____________ of the substance deposited by the passage of 1 coulomb of electricity.
a) Volume
b) Weight
c) Density
d) Velocity

View Answer

Answer: b [Reason:] Electrochemical equivalent may be defined as the weight of the substance deposited by the passage of 1 coulomb of electricity. The electrochemical equivalent of an element is measured with a voltameter.

3. 1 Faraday =
a) 1 coulomb
b) 1000 coulomb
c) 5000 coulomb
d) 96500 coulomb

View Answer

Answer: d [Reason:] 1 Faraday = 96,500 Coulomb. It is calculated mathematically and is widely used everywhere.

4. According to Faraday’s second law, the weights of different substances evolved by the passage of same quantity of electricity are proportional to their
a) Chemical equivalent weight
b) Current supply
c) Chemical equivalent density
d) Volume

View Answer

Answer: a [Reason:] According to Faraday’s second law, the weights of different substances evolved by the passage of same quantity of electricity are proportional to their chemical equivalent weights. For Faraday’s second law, Q, F, and z are constants, so that the larger the value of M/z (equivalent weight) the larger m will be.

5. Silver is electrodeposited on a metallic vessel of surface area 800 cm2 by passing a current of 0.2 A for 3 hours. The thickness of silver deposited is
a) 0.1 mm
b) 0.02 mm
c) 0.05 mm
d) 0.2 mm

View Answer

Answer: b [Reason:] The thickness of silver deposited is 0.0288 mm. It is calculated mathematically.

6. The velocity with which an ion moves under a potential gradient of __________ volt/cm in a solution is called ionic mobility.
a) 5
b) 4
c) 3
d) 1

View Answer

Answer: d [Reason:] The velocity with which an ion moves under a potential gradient of one volt/cm in a solution is called ionic mobility. The separation of ions according to their mobility in gas phase is called ion mobility spectrometry, in liquid phase it is called electrophoresis.

7. The unit of ionic mobility in SI system is
a) msV-1
b) m3sV2
c) m2s-1V-1
d) m2s-1V

View Answer

Answer: c [Reason:] The unit of ionic mobility in SI system is m2s-1V-1. The separation of ions according to their mobility in gas phase is called ion mobility spectrometry, in liquid phase it is called electrophoresis.

8. Which of the following factor does not affect ionic mobility?
a) Pressure
b) Nature of ions
c) Temperature
d) Concentration of the solution

View Answer

Answer: a [Reason:] The factors which affects the ionic mobility are- nature of the ions, concentration of the solution, temperature and the applied potential difference. It does not get affected by pressure.

9. State true or false. Faraday constant is the amount of electricity present in 100 moles of electrons.
a) True
b) False

View Answer

Answer: b [Reason:] Faraday constant is the amount of electricity present in 1 mole of electrons. It is equal to 96500 C mol-1

10. The molecular formula of cryolite is
a) Al2O3
b) Fe2O3
c) Na3AlF6
d) Na3MgI6

View Answer

Answer: c [Reason:] The molecular formula of cryolite is Na3AlF6. Cryolite is used as an insecticide and a pesticide. It is also used to give fireworks a yellow color.

11. Refined bauxite is dissolved in molten cryolite at a temperature slightly below
a) 00C
b) 1000C
c) 20000C
d) 10000C

View Answer

Answer: d [Reason:] Refined bauxite is dissolved in molten cryolite at a temperature slightly below 10000C. Cryolite is used as an insecticide and a pesticide. It is also used to give fireworks a yellow color.

12. State true or false. Aluminium and its alloys can be given shapes of pipes, tubes, rods, wires, plates or foils.
a) True
b) False

View Answer

Answer: a [Reason:] Aluminium and its alloys can be given shapes of pipes, tubes, rods, wires, plates or foils. Aluminium is one of the most widely used element. The main alloying agents of aluminium are copper, zinc, magnesium, manganese, and silicon

Set 5

1. The tensile strength of fiber is
a) Very Low
b) Low
c) High
d) Intermediate

View Answer

Answer: c [Reason:] The tensile strength of fiber is high and depends upon the strength of chemical bonds of the polymer chains.

2. Which of the following type of bonding maintains the alignment of chains of the polyester?
a) Vander Waal’s force
b) Dipole-dipole attraction
c) Hydrogen bonding
d) Covalent bonding

View Answer

Answer: b [Reason:] Dipole-dipole attraction are induced due to the dipole formed by alignment of negative and positive charges and hence this type of bonding maintains the alignment of chains of the polyester.

3. Nylon-66, PET and PAN all have Tg around
a) 100 0C
b) 200 0C
c) 300 0C
d) 500 0C

View Answer

Answer: a [Reason:] Nylon-66, PET and PAN all have Tg around 100 0C. The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs. It is always lower than the melting temperature, of the crystalline state of the material, if one exists.

4. Hydrogen bonding is responsible for maintaining the alignment of
a) Stereoregular chains of isotactic polypropylene
b) Polyesters
c) Polyacrylonitrile
d) Polyamides

View Answer

Answer: d [Reason:] Hydrogen bonding is responsible for maintaining the alignment of polyamides and polyurethanes. Polyamides are polymer of a type made by the linkage of an amino group of one molecule and a carboxylic acid group of another.

5. Nylon-6 can be prepared by ring opening polymerisation of
a) Amino caproic acid
b) Caprolactum
c) Adipic acid
d) Terephthalic acid

View Answer

Answer: b [Reason:] Nylon-6 can be prepared by ring opening polymerisation of caprolactum. Caprolactum has 6 carbons and hence, Nylon-6.

6. Which of the following is the third step for the synthesis of nylon-6?
a) Conversion of cyclohexane into cyclohexanone
b) Ring opening polymerisation of caprolactum
c) Conversion of cyclohexanone-oxime into caprolactum
d) Conversion of cyclohexanone into cyclohexanone-oxime

View Answer

Answer: c [Reason:] Conversion of cyclohexane into cyclohexanone is the initial step. Then the second step is the conversion of cyclohexanone into cyclohexanone-oxime and then the conversion of cyclohexanone-oxime into caprolactum is the third step for the synthesis of nylon-6. Ring opening polymerisation of caprolactum is the last step.

7. The cyclohexanone is converted into cyclohexanone-oxime by
a) Treatment with hydroxylamine
b) Oxidation
c) Reduction
d) Backmann rearrangement

View Answer

Answer: a [Reason:] The cyclohexanone is converted into cyclohexanone-oxime by treatment with hydroxylamine because hydroxylamine act as catalyst for this reaction. This is the second step for the synthesis of Nylon-6.

8. Nylon-6,6 is made by the condensation polymerisation of hexamethylene diamine and adipic acid in the molar ratio of
a) 2 : 3
b) 1 : 2
c) 3 : 5
d) 1 : 1

View Answer

Answer: d [Reason:] Nylon-6, 6 is made by the condensation polymerisation of hexamethylene diamine and adipic acid in the molar ratio of 1 : 1. Equivalent amounts of hexamethylene diamine and adipic acid are combined with water in a reactor.

9. The nylon-6, 6 have high crystallinity which imparts
a) Low strength
b) Low meting point
c) Toughness and elasticity
d) Retention to poor mechanical properties

View Answer

Answer: c [Reason:] The nylon-6, 6 have high crystallinity which imparts high strength, high melting point, elasticity, toughness and retention to good mechanical properties.

10. State true or false. Nylons are polar polymers and have good hydrocarbon resistance.
a) True
b) False

View Answer

Answer: a [Reason:] Nylons are polar polymers and have good hydrocarbon resistance. Nylon resins are widely used in the automobile industry especially in the engine compartment.