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Multiple choice question for engineering

Set 1

1. The atom which defines the structure of a family of organic compounds and their properties is called
a) Resonating structure
b) Homologous structure
c) Functional group
d) Nucleophile

View Answer

Answer: c [Reason:] The atom which defines the structure of a family of organic compounds and their properties is called functional group. Functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules.

2. The functional group in alkyl halide is
a) Hydroxyl group
b) Halogen atom
c) Inert gas
d) All of the mentioned

View Answer

Answer: b [Reason:] The functional group in alkyl halide is halogen atom. Halide refers to halogen. Halogens are a group in the periodic table consisting of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

3. The halide ion is an extremely
a) Weak base
b) Weak acid
c) Strong base
d) Strong acid

View Answer

Answer: a [Reason:] The halide ion is an extremely weak base because hydrogen halide are acidic as they release a proton.

4. When the nucleophile :OR attacks the RX, the resultant product will be
a) R – OH
b) ROR
c) R:CN
d) RNHR

View Answer

Answer: b [Reason:] When the nucleophile :OR attacks the RX, the resultant product will be ROR. X will be separated.

5. Select the correct statement from the following option.
a) SN2 reaction follows second order kinetics
b) No intermediate is involved in SN2 mechanism
c) SN2 reactions are one-step reaction
d) All of the mentioned

View Answer

Answer: d [Reason:] SN2 reaction follows second order kinetics and no intermediate is involved in it. So, SN2 reactions are one-step reaction.

6. The reactivity order of alkyl halides in SN2 is
a) CH3 X > 10 > 20 > 30
b) CH3 X > 20 > 10 > 30
c) CH3 X > 30 > 10 > 20
d) CH3 X > 30 > 20 > 10

View Answer

Answer: a [Reason:] The correct order of reactivity in alkyl halide is- CH3 X > 10 > 20 > 30. CH3 X is most reactive whereas 30 is least reactive.

7. State true or false. SN1 reaction involves heterolysis to form the carbocation as an intermediate.
a) True
b) False

View Answer

Answer: a [Reason:] SN1 reaction involves heterolysis to form the carbocation as an intermediate.

8. Which step in SN1 reaction is a slow rate determining step?
a) Attack of nucleophile
b) Formation of racemic mixture
c) Formation of transition state
d) All of the mentioned

View Answer

Answer: c [Reason:] The first step of formation of transition state is a slow rate determining step in SN1 reaction.

9. A low concentration of nucleophile favours the
a) SN2 reaction
b) SN1 reaction
c) Both SN1 and SN1 reaction
d) None of the mentioned

View Answer

Answer: b [Reason:] A low concentration of nucleophile favours the SN1 reaction but high concentration of nucleophile favours the SN2 reaction.

10. Which of the following reactions are favoured by polar aprotic solvent?
a) SN1 reactions
b) SN2 reactions
c) Both SN1 and SN1 reactions
d) None of the mentioned

View Answer

Answer: b [Reason:] SN1 reactions are favoured by polar protic solvents whereas SN2 reactions are favoured by polar aprotic solvent.

11. Arrange the following in the decreasing order of leaving group in nucleophilic substitution reaction.
a) H > Cl > HO > Br > CH3COO
b) Cl > Br > HO > H > CH3COO
c) Cl > Br > CH3COO > HO > H
d) HO > CH3COO > H > Br > Cl

View Answer

Answer: c [Reason:] The correct order is- Cl > Br > CH3COO > HO > H.

12. Reaction of alcohol with SOCl2 is
a) SN1
b) SN2
c) SNAr
d) SNi

View Answer

Answer: d [Reason:] Reaction of alcohol with SOCl2 proceeds with retention of configuration via substitution nucleophilic internal (SNi) mechanism.

13. The nucleophilic substitutions do not occur in haloarenes because
a) The carbon-halogen bond is much shorter
b) The carbon-halogen bond is stronger compared to that in haloalkanes
c) The lone pair of electrons on the halogen participates in delocalisation with the π-electrons of benzene ring
d) All of the mentioned

View Answer

Answer: d [Reason:] The nucleophilic substitutions do not occur in haloarenes because the carbon-halogen bond is much shorter and stronger compared to that in haloalkanes and the lone pair of electrons on the halogen participates in delocalisation with the π-electrons of benzene ring.

14. Which of the following drastic condition is required for the substitution in haloarenes?
a) High temperature
b) High pressure
c) Strong concentrated reagent
d) All of the mentioned

View Answer

Answer: d [Reason:] Drastics conditions like high temperature, high pressure and strong concentrated reagents are used to carry substitution in haloarenes.

15. The rate of nucleophilic substitution reactions are higher in the presence of
a) Electron withdrawing groups
b) Electron releasing groups
c) Both electron withdrawing and releasing groups
d) None of the mentioned

View Answer

Answer: a [Reason:] The rate of nucleophilic substitution reactions are higher in the presence of electron withdrawing groups.

Set 2

1. Melting point of fat is _________ and melting point of oil is ________.
a) Higher, higher
b) Lower, lower
c) Higher, lower
d) Lower, higher

View Answer

Answer: c [Reason:] Melting point of fat is higher and melting point of oil is lower. Generally, healthy fats have a high amount of monounsaturated fats as well as polyunsaturated fats and a low amount of saturated fats.

2. Which of the following is an example of fats?
a) Glyceryl trioleate
b) Vegetable ghee
c) Coconut oil
d) Groundnut oil

View Answer

Answer: b [Reason:] Vegateble ghee is an example of fats. Glyceryl trioleate, Coconut oil and groundnut oil are the examples of oils.

3. Select the incorrect statement from the following option.
a) Oils are saturated triglyceride
b) Oils have lower melting points
c) Oils are liquid at room temperature
d) Examples of oils are glyceryl trioleate, coconut oil, olive oil, etc

View Answer

Answer: a [Reason:] Oils are partially unsaturated triglyceride which have lower melting point and are liquid at room temperature.

4. Which of the following is not a suitable solvent for oils and fats?
a) Benzene
b) CCl4
c) CHCl3
d) Water

View Answer

Answer: d [Reason:] Oils and fats are soluble in benzene, CCl4, CHCl3 and other organic solvents.

5. State true or false. Oils and fats are good conductors of heat and electricity.
a) True
b) False

View Answer

Answer: b [Reason:] Oils and fats are poor conductors of heat and electricity. They do not allow heat or electricity to pass through them.

6. Saponification is hydrolysis
a) By alkalis
b) In digestive tracts of human beings
c) By acids
d) By salts

View Answer

Answer: a [Reason:] Saponification is the alkaline hydrolysis of the fatty acid esters. Example: The chemical reaction between any fat and sodium hydroxide is a saponification reaction.

7. Which of the following act as catalyst in digestive tracts of human beings?
a) Lewis acid
b) Lewis base
c) Hydrogen peroxide
d) Lipases

View Answer

Answer: d [Reason:] Lipases are the enzymes which act as catalyst in the hydrolysis in digestive tracts of human beings.

8. Hydrogenation is conversion of unsaturated acid groups into the saturated one by catalyst
a) Ti
b) Pb
c) Ni
d) Sn

View Answer

Answer: c [Reason:] Hydrogenation is conversion of unsaturated acid groups into the saturated one by metal Nickel (Ni) catalyst.

9. Vegetable ghee is manufactured by
a) Saponification
b) Hydrogenation
c) Oxidation polymerisation
d) Reduction polymerisation

View Answer

Answer: b [Reason:] Vegetable ghee is manufactured by hydrogenation. But due to the trans fatty acids dilemma, partial hydrogenation is no longer viable

10. Hydrogenolysis is a reaction which leads to the reduction products of
a) Aldehyde
b) Ketone
c) Alcohol
d) Ester

View Answer

Answer: c [Reason:] Hydrogenolysis is a reaction which leads to the formation of glycerol and reduction products of alcohol.

Set 3

1. State true or false. Optical activity is the property in which a substance is unable to rotate the plane of polarisation.
a) True
b) False

View Answer

Answer: b [Reason:] Optical activity is the property in which a substance is able to rotate the plane of polarisation of plane polarised light.

2. Select the incorrect statement from the following option.
a) Racemic modification is an equimolar mixture of dextrorotatory and levorotatory isomers
b) Meso compounds contains more than one chiral carbon centre
c) Meso compounds are externally compensated
d) Racemic mixture is designated as dl-pair

View Answer

Answer: c [Reason:] Meso compounds are internally compensated form whereas racemic mixtures are externally compensated modification. All the other options are correct.

3. Select the correct statement from the following option.
a) Meso compound possess both plane of symmetry and centre of symmetry
b) Meso compound possess either plane or centre of symmetry
c) Meso compound does not possess either plane or centre of symmetry
d) Meso compounds are externally compensated form

View Answer

Answer: b [Reason:] Meso compound possess either plane or centre of symmetry. They do not possess both plane of symmetry and centre of symmetry and also they are internally compensated form.

4. How many optical isomers are possible in a compound with one chiral carbon?
a) 5
b) 4
c) 2
d) 3

View Answer

Answer: d [Reason:] A compound with one chiral carbon has three optical isomers (+), (-) and (±).

5. Which of the following compound would show optical isomerism?
a) CH3 – CH(OH) COOH
b) H2N CH(CH3)2
c) (CH3)2 CHCHO
d) H2N CH2 COOH

View Answer

Answer: a [Reason:] CH3 – CH(OH) COOH will show optical isomerism as it possess chiral carbon.

6. The number of configurational isomers of molecules having (n) different chiral carbons is
a) 2n
b) 2n
c) 2n-1
d) 2n+1

View Answer

Answer: b [Reason:] The number of configurational isomers of molecules having (n) different chiral carbons is 2n. It is calculated mathematically.

7. The number of racemic forms of molecules having (n) different chiral carbons is
a) 2n
b) 2n
c) 2n-1
d) 2n+1

View Answer

Answer: c [Reason:] The number of racemic forms of molecules having (n) different chiral carbons is 2n-1 whereas the number of configurational isomers of molecules having (n) different chiral carbons is 2n.

8. For a molecule with two like chiral carbon atoms, the number of optically inactive form is
a) 1
b) 2
c) 3
d) 4

View Answer

Answer: a [Reason:] For a molecule with two like chiral carbon atoms, the number of optically inactive form is one. This is always used for the calculation of optically inactive forms.

9. For a molecule with two like chiral carbon atoms, the number of optically active form is
a) 4
b) 3
c) 1
d) 2

View Answer

Answer: d [Reason:] For a molecule with two like chiral carbon atoms, the number of optically active form is two. This is always used for the calculation of optically active forms.

10. Find the number of stereoisomers for CH3 – CHOH – CH = CH – CH3.
a) 1
b) 2
c) 3
d) 4

View Answer

Answer: d [Reason:] The number of stereoisomers for CH3 – CHOH – CH = CH – CH3 is four. This is calculated by the formula 2n+1.

11. State true or false. The necessary condition for showing optical activity is the chirality of a molecule as a whole.
a) True
b) False

View Answer

Answer: a [Reason:] The necessary condition for showing optical activity is the chirality of a molecule as a whole. It is the most important condition for showing optical activity.

12. The sufficient condition for showing optical activity is
a) Molecule should have measurable amount of optical activity only
b) Polarimeter should have capacity of recording low-degree optical activity only
c) Chirality of molecule as a whole only
d) Both, the molecule should have measurable amount of optical activity and polarimeter should have capacity of recording low-degree optical activity

View Answer

Answer: d [Reason:] The molecule should have measurable amount of optical activity and polarimeter should have capacity of recording low-degree optical activity.

13. Which of the following is an example of optically active compounds without chirality?
a) Tartaric acid
b) Sulfhonium salt
c) Diphenic acid
d) Glyceraldehyde

View Answer

Answer: b [Reason:] Sulphhonium salt is an example of optically active compounds without chirality. It is a special case. There are various such molecules which are optically active compounds without chirality.

14. State true or false. Spiranes exhibit optical isomerism because of restricted rotation.
a) True
b) False

View Answer

Answer: a [Reason:] Spiranes exhibit optical isomerism because of restricted rotation. They cannot rotate about any axis.

15. Which of the following is not optically active compound?
a) 1,7- Dicarboxylic spirocycloheptane
b) 1,3- Diphenyl propadiene
c) Meso-tartaric acid
d) Glyceraldehyde

View Answer

Answer: c [Reason:] Meso-tartaric acid is optically inactive molecule with chiral carbon atom. It is a special case of optical activity.

Set 4

1. Reaction kinetics deals with the study of
a) Rate of reaction
b) Mechanism of reaction
c) Factors which affects the rate of reaction
d) All of the mentioned

View Answer

Answer: d [Reason:] Reaction kinetics deals with the study of rate of reaction, their mechanism and the factors which affects the rate of reaction. It specifies all the general characteristics of a chemical reaction.

2. The reaction rate is defined as the rate at which the concentration of the reactants __________ with time or the concentration of products ___________ with time.
a) Increase, increase
b) Decrease, decrease
c) Decrease, increase
d) Increase, decrease

View Answer

Answer: c [Reason:] The reaction rate is defined as the rate at which the concentration of the reactants decreases with time or the concentration of products increases with time.

3. The unit of rate of reaction is
a) Mol L-1 s-1
b) Mol L s-1
c) Mol L-1 s
d) Mol L s

View Answer

Answer: a [Reason:] The unit of rate of reaction is Mol L-1 s-1. The reaction rate is defined as the rate at which the concentration of the reactants decreases with time or the concentration of products increases with time.

4. State true or false. The order of the reaction can be zero, fractional or integer and it is always experimentally determined.
a) True
b) False

View Answer

Answer: a [Reason:] The order of the reaction can be zero, fractional or integer and it is always experimentally determined.The order of reaction with respect to a given substance is defined as the index, or exponent, to which its concentration term in the rate equation is raised.

5. The reaction rate constant may be defined as the rate of the reaction when the concentration of each reactants is
a) Zero
b) Unity
c) Doubled the initial concentration
d) Infinite

View Answer

Answer: b [Reason:] The reaction rate constant may be defined as the rate of the reaction when the concentration of each reactants is unity. A reaction rate constant or reaction rate coefficient, k, quantifies the rate of a chemical reaction.

6. The unit s-1 is the unit of rate constant for the reaction of the order
a) 1
b) 2
c) 0.5
d) 0

View Answer

Answer: d [Reason:] The unit s-1 is the unit of rate constant for the reaction of the order zero. It quantifies the rate of a chemical reaction.

7. The unit of rate constant for the second order reaction will be
a) s-1
b) L mol-1 s-1
c) Mol0.5 L-0.5 s-1
d) Mol L-1 s-1

View Answer

Answer: c [Reason:] The unit of rate constant for the second order reaction will be mol0.5 L-0.5 s-1.

8. What will be the order of reaction if the rate law is given by:
Rate = k [SO2]1 [SO3]-0.5
a) 1
b) 0.5
c) 2
d) -0.5

View Answer

Answer: b [Reason:] The order of the reaction will be 0.5. It is given by : Order = 1-0.5 = 0.5.

9. State true or false. Order of a reaction does not give any information about the reaction mechanism.
a) True
b) False

View Answer

Answer: a [Reason:] Order of a reaction does not give any information about the reaction mechanism. It only gives the idea of the reactant species taking part in a reaction.

10. The unit L mol-1 s-1 is the unit of rate constant for the reaction of the order
a) 0
b) 1
c) 0.5
d) 2

View Answer

Answer: c [Reason:] The unit L mol-1 s-1 is the unit of rate constant for the reaction of the order 0.5. This is a half-order reaction.

Set 5

1. Which of the following is used for making rechargeable batteries?
a) Polypyrrole
b) Polyester
c) Polyaniline
d) Polyacrylonitrile

View Answer

Answer: c [Reason:] Polyaniline is used for making rechargeable batteries in the shape of flat buttons or as laminated rolled films.

2. The advantage of using conducting polymers in place metals is their
a) Cost
b) Light-weight
c) Thermal conductivity
d) Solubility

View Answer

Answer: b [Reason:] The advantage of using conducting polymers in place metals is their light-weight and they do not corrode.

3. During the polymerisation of polyaniline, the sequence of the colour change is
a) Green >> copper tint >> blue green >> light blue
b) Light blue >> blue green >> copper tint >> green
c) Copper tint >> blue green >> green >> light blue
d) Blue green >> green >> light blue >> copper tint

View Answer

Answer: b [Reason:] During the polymerisation of polyaniline, the sequence of the colour change is- Light blue >> blue green >> copper tint >> green.

4. The precipitate is dried under vacuum at 60-80 0C for
a) 1 hour
b) 2 hours
c) 5 hours
d) 8 hours

View Answer

Answer: d [Reason:] The precipitate is dried under vacuum at 60-80 0C for 8hours for complete dehydration process.

5. The color of emaraldine salt which is obtained is
a) Copper tint
b) Blue green
c) Green
d) Light blue

View Answer

Answer: c [Reason:] The color of emaraldine salt which is obtained is green. The emeraldine salt form of polyaniline is highly electrically conducting.

6. The final washings of the salt is done with
a) Distilled water
b) Diethyl ether
c) Methanol
d) Acetone

View Answer

Answer: b [Reason:] The final washings of the salt is done with diethyl ether for cleaning it completely.

7. State true or false. Conducting polymers having conjugation is a type of intrinsically conducting polymers.
a) True
b) False

View Answer

Answer: a [Reason:] Conducting polymers having conjugation is a type of intrinsically conducting polymers. They do not conduct extrinsically.

8. Which of the following is not true for intrinsically conducting polymers?
a) Low conductivities
b) Poor mechanical strength
c) Improcessability
d) Good storage stability

View Answer

Answer: d [Reason:] Intrinsically conducting polymers have poor storage stability leading to its loss in conductivity.

9. Select the incorrect statement from the following option.
a) Conductive element filled polymer possess good bulk conductivity
b) Conductive element filled polymer are generally high in cost
c) Conductive element filled polymer are light in weight
d) Conductive element filled polymer are mechanically durable and strong

View Answer

Answer: b [Reason:] Conductive element filled polymer are generally low in cost. All the other options are correct.

10. Which of the following is not an application of conducting polymers?
a) Rechargeable batteries
b) Analytical sensors
c) Electronics
d) Adhesives

View Answer

Answer: d [Reason:] Rechargeable batteries, analytical sensors, electronics are some of the applications of conducting polymers.

11. State true or false. Emeraldine base form of polyaniline is used as resist for lithography.
a) True
b) False

View Answer

Answer: a [Reason:] Emeraldine base form of polyaniline is used as resist for lithography. The synthesis of polyaniline nano structures is facile.

12. Bakelite is
a) Gel
b) Gas
c) Solid
d) Liquid

View Answer

Answer: c [Reason:] Bakelite is soild. It is a thermosetting phenol formaldehyde resin, formed from a condensation reaction of phenol with formaldehyde.