Category: Engineering Chemistry Objective Questions

250+ TOP MCQs on Liquid Fuels and Answers

Engineering Chemistry Multiple Choice Questions on “Liquid Fuels”.

1. How can we obtain liquid coal synthetically?
a) Carbonisation of coal
b) Hydrogenation of coal
c) By heating of coal
d) By cooling of coal
Answer: b
Clarification: Highly volatile bituminous coal is used for the hydrogenation process. The hydrogenation of bituminous coal produces liquid hydrocarbons which have a number of uses in many processes. It is obtained by the Bergius process.

2. In which processes does the low boiling fractions of petroleum are used?
a) Petrol engines
b) Diesel engines
c) Oil fired furnaces
d) Kerosene engines
Answer: a
Clarification: At low boiling fractions of petroleum least amount of impurities are left and since the efficiency petrol engine decreases with the increase in the amount of impurities, these fractions are used in petrol engines. At high boiling fractions, diesel engines and oil fired furnaces are used.

3. Which of the following fuel requires less storage space?
a) Methane gas
b) Coal
c) Cow dunk
d) Kerosene
Answer: d
Clarification: Liquid fuels require less storage space as compared to solid and gaseous fuel. Kerosene weigh 30% less and occupy 50% less space than coal of equal heating value. Gaseous fuel are weigh very less, but their storage requires a big space.

4. Liquid fuels leave ash content after burning.
a) True
b) False
Answer: b
Clarification: Both liquid and gaseous fuel does not produce ash content after burning as solid fuel. The problem of clinker formation is totally absent in case of liquid fuel.

5. Which type of combustion is seen in liquid fuel?
a) Uniform and complete combustion
b) Non-uniform and complete combustion
c) Uniform and incomplete combustion
d) Non-uniform and incomplete combustion
Answer: a
Clarification: The rate of combustion in the case of liquid fuels can be controlled easily. Also since there is no ash generation in liquid fuel, it undergoes complete combustion.

6. Which of the following fuel does not requires excess air for its combustion?
a) Coal
b) Cow-dunk cake
c) Diesel
d) Charcoal
Answer: c
Clarification: Liquid fuel such as diesel does not require excess air for their combustion, they normally start combustion on catching fire where as in solid fuels excess air is required for the process of combustion. Pulverised coal does not require excess air for combustion.

7. Liquid fuel produces _____________ odours on incomplete combustion.
a) Pleasant
b) Unpleasant
c) No odours
d) Fruity
Answer: b
Clarification: Sometimes due to the presence of impurities, incomplete combustion of liquid fuel occurs which produces very unpleasant odours which can also be hazardous for health. For this process purification method is used.

8. What happens when liquid fuels evaporate?
a) It increases its calorific value
b) It reduces the impurities present in it
c) It increase the ash content present in it
d) It makes losses and leakages in the container
Answer: d
Clarification: The containers in which the liquid fuels are stored are made of special material due the possibility of losses due to evaporation and leakage in the containers. The liquid fuels cannot be stored in containers for long time.

9. Which kind of liquid fuels are risky to store?
a) Flammable and volatile
b) Inflammable and volatile
c) Flammable and non-volatile
d) Inflammable and non-volatile
Answer: b
Clarification: I the temperature of the surrounding increases to a high value, then the inflammable liquid fuels will burn quickly. And the presence of volatile matter will cause the liquid fuels to burn with long flames.

10. Which kind of burners are used for efficient combustion of liquid fuels?
a) Wesman burner
b) Dual-fuel burner
c) Oil burners
d) Pressure jet burner
Answer: a
Clarification: Wesman burner is used of high efficiency combustion of both liquid and gaseous fuel. Special types of sprayers are also used efficient combustion of liquid fuels.

250+ TOP MCQs on Efficiency of Combustion and Answers

Engineering Chemistry Multiple Choice Questions on “Efficiency of Combustion”.

1. Which of the following is the correct condition for the efficient combustion of coal?
a) Coal should be of high calorific value
b) Intimate mixing of air with the combustible matter
c) The ignition temperature should be high
d) The volatile matter should be low
Answer: b
Clarification: For efficient combustion, it is essential that the coal and its distillation products are brought into intimate contact with sufficient quantity of air to burn all combustible material. Also, sufficient time should be allowed to complete the combustion process.

2. Which of the following furnace is best suitable for the efficient combustion of coal?
a) Blast furnace
b) Pudding furnace
c) Open hearth furnace
d) Boiler furnace
Answer: d
Clarification: This type of furnaces are used for efficient combustion of coal since these convert the heat into thermal energy which are then used for generation of power. Pudding furnace and open hearth furnaces are types of steelmaking furnaces.

3. Which of the following is calculated by flue gas analysis?
a) Amount of air used in combustion
b) Rate of combustion
c) Time required for combustion
d) Amount of air present after combustion
Answer: a
Clarification: The only practical way for determining the amount of air used in furnace is to analyse the flue gas for the constituents CO2, CO an O2. The control of air is by means of dampers.

4. What happens when carbon monoxide is obtained in flue gas analysis?
a) Combustion is complete
b) Combustion does not take place
c) Combustion is incomplete
d) It increases the rate of combustion.
Answer: c
Clarification: If the analysis shows the presence of free CO, it means that the combustion is incomplete which calls for an intermediate increase in the amount of air used for combustion. Also, a diminution in the rate of supply of coal is required.

5. Which of the following compound other than CO2, CO an O2 can be determined by the flue gas analysis?
a) C2H6
b) C6H6
c) C6H11O22
d) Ethylene
Answer: a
Clarification: Sometimes N2, H2 and hydrocarbons like CH4 and C2H6 are obtained by flue gas analysis of coal. If N2 is obtained after the analysis, the combustion will be incomplete.

6. What happens when too much excess air is supplied to the furnace in the process of combustion of coal?
a) There is a gain in heat in the furnace
b) No change occurs in the furnace
c) There is loss in heat in the furnace
d) The excess air escapes out
Answer: c
Clarification: In ordinary furnaces, 50 to 100 % excess air is generally supplied. If the excess air is supplied above this amount, there is a loss of heat in the furnace. In such cases, the supply of air to the hearth is cut short or the rate of fuel supply is increased.

7. If both CO and O2, both are indicated in the appreciable amount in the flue gas analysis, which type of combustion is seen?
a) Regular and non-uniform combustion
b) Irregular and non-uniform combustion
c) Regular and uniform combustion
d) Irregular and uniform combustion
Answer: b
Clarification: If both CO and O2 are present in an appreciable amount, then the combustion is irregular and non-uniform. That means, in some parts of the furnace, there is an excess of air and in some other parts, the supply of air is insufficient.

8. Short orsat apparatus gives more precise results than long orsat in the analysis of flue gas.
a) True
b) False
Answer: b
Clarification: Long orsat or precision model orsat is used for analysis of quite complicated mixtures and which gives very accurate results in competent hands. The precision orsat assemblies are mounted on substantial stands.

9. At what temperature does the CO is converted to CO2 in orsat apparatus for analysis of flue gas?
a) 280-295 0C
b) 250-265 0C
c) 350-365 0C
d) Less than 100 0C
Answer: a
Clarification: At the temperature range of 280-295 0C, the CO is converted into CO2. Also the hydrogen present is oxidised to water. The diminution in the volume of gas sample indicates the volume of hydrogen.

10. Which of the following apparatus cannot be used for flue gas analysis?
a) Ambler’s apparatus
b) Hemple’s apparatus
c) Able’s apparatus
d) Bunte’s apparatus
Answer: c
Clarification: Able’s apparatus is used for calculation of flash point and fire point of an oil. Flash point is the minimum temperature of oil, at which the vapours of oil produces flash in a burning match stick when brought close to the vapours of oil.

250+ TOP MCQs on Galvanic Series and Answers

Engineering Chemistry Multiple Choice Questions on “Galvanic Series”.

1. Galvanic series gives real and useful information regarding the ____________
a) Electrical conductivity of metals and alloys
b) Thermal conductivity of metals and alloys
c) Corrosion behaviour of metals and alloys
d) Oxidation power of metals and alloys
Answer: c
Clarification: Galvanic series gives real and useful information regarding the corrosion behaviour of metals and alloys in a given environment, i.e. which metal will corrode at a faster rate and which will not corrode at all.

2. Which of the following is the most noble metal?
a) Gold
b) Graphite
c) Titanium
d) Platinum
Answer: d
Clarification: Platinum is the most noble metal present at the protected end of galvanic series. It does not corrode easily.

3. Which of the following is the least noble metal?
a) Magnesium
b) Brass
c) Aluminium
d) Nickel
Answer: a
Clarification: Magnesium is the least noble metal present at the corroded end of the galvanic series. It corrodes very easily and at very fast rate.

4. Arrange the following in the ascending order of their degree of corrosion.
a) Zinc >> Magnesium >> Copper >> Lead >> Aluminium
b) Copper >> Lead >> Aluminium >> Zinc >> Magnesium
c) Zinc >> Magnesium >> Lead >> Copper >> Aluminium
d) Copper >> Aluminium >> Zinc >> Lead >> Magnesium
Answer: b
Clarification: The correct order is Copper >> Lead >> Aluminium >> Zinc >> Magnesium. Magnesium is the most active towards corrosion and copper is the least active towards corrosion among the given elements.

5. As the distance between the two metals increases in the galvanic series, the degree of corrosion ____________
a) Increases
b) Decreases
c) Remains same
d) First increases then decreases
Answer: a
Clarification: As the distance between the two metals increases in the galvanic series, the degree of corrosion increases. elements are arranged in the decreasing order of corrosion in the galvanic series.

6. Which of the following metals are protected metals?
a) Present at the top
b) Present at the middle
c) Present at the bottom
d) Both present at the top and the bottom
Answer: c
Clarification: The metals which are present at the bottom of the galvanic series are the protected metals. These are the least active towards corrosion and hence also called noble or protected metals.

7. Which electrode is used for measuring electrode potential as a standard electrode in galvanic series?
a) Hydrogen electrode
b) Calomel electrode
c) Oxygen electrode
d) Nitrogen electrode
Answer: b
Clarification: Calomel electrode is used for measuring electrode potential as a standard electrode in galvanic series. it gives the value of electrode potential of different electrodes.

8. The galvanic series predicts the relative displacement tendencies of metals and non-metals in electrolytes containing a particular concentration of salts.
a) True
b) False
Answer: b
Clarification: The galvanic series predicts the corrosion tendencies of metals and non-metals in the actual environment. It has been drawn up for metals and alloys in sea water, which shows their relative nobility.

9. The phenomenon by which a metal or alloy show high corrosion resistance due to the formation of the highly protective film is called ____________
a) Electrolysis
b) Electrodialysis
c) Galvanisation
d) Passivation
Answer: d
Clarification: The phenomenon by which a metal or alloy shows high corrosion resistance due to the formation of the highly protective film is called passivation. Passivation is the use of a light coat of protective material, such as metal oxide, to create a shell against corrosion.

10. The thickness of the protective film in passivation is about ____________
a) 1 mm
b) 0.02 mm
c) 0.0004 mm
d) 0.004 mm
Answer: c
Clarification: The thickness of the protective film in passivation is about 0.0004 mm. Passivation is the use of a light coat of protective material, such as metal oxide, to create a shell against corrosion.

250+ TOP MCQs on Optical Isomerism and Answers

Engineering Chemistry Multiple Choice Questions on “Optical Isomerism”.

1. Optical activity is the property in which a substance is unable to rotate the plane of polarisation.
a) True
b) False
Answer: b
Clarification: 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 contain more than one chiral carbon centre
c) Meso compounds are externally compensated
d) Racemic mixture is designated as dl-pair
Answer: c
Clarification: 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
Answer: b
Clarification: 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
Answer: d
Clarification: 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
Answer: a
Clarification: 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
Answer: b
Clarification: 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
Answer: c
Clarification: 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
Answer: a
Clarification: 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
Answer: d
Clarification: 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
Answer: d
Clarification: The number of stereoisomers for CH3 – CHOH – CH = CH – CH3 is four. This is calculated by the formula 2n+1.

11. The necessary condition for showing optical activity is the chirality of a molecule as a whole.
a) True
b) False
Answer: a
Clarification: 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
Answer: d
Clarification: 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
Answer: b
Clarification: 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. Spiranes exhibit optical isomerism because of restricted rotation.
a) True
b) False
Answer: a
Clarification: 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
Answer: c
Clarification: Meso-tartaric acid is an optically inactive molecule with a chiral carbon atom. It is a special case of optical activity.

250+ TOP MCQs on Column Chromatography and Answers

Engineering Chemistry Multiple Choice Questions on “Column Chromatography”.

1. Column chromatography is based on the principle of _______________
a) Ion-exchange
b) Exclusion principle
c) Differential adsorption
d) Absorption
Answer: c
Clarification: Column chromatography is based on the principle of differential adsorption. It means different compounds have different tendencies to get adsorb on a particular surface.

2. Arrange the following compounds in order of their increasing adsorption tendencies.
a) Cellulose >> starch >> calcium carbonate >> alumina
b) Cellulose >> starch >> alumina >> charcoal
c) Charcoal >> cellulose >> alumina >> starch
d) Calcium carbonate >>; alumina >> starch >> cellulose
Answer: a
Clarification: Cellulose >> starch >> calcium carbonate >> charcoal >> alumina is the correct order of increasing adsorption tendencies.

3. What is the factor responsible for the separation in column chromatography?
a) Polarity differences between the solvent
b) Polarity differences between the solute
c) Polarity indifference between the solvent
d) Polarity indifference between the solute
Answer: b
Clarification: Polarity differences between the solute molecules are responsible for the separation in column chromatography.

4. Select the correct statement from the following options.
a) The lesser the polarity of solute, more strongly it will be adsorbed on a polar surface
b) The greater the polarity of solute, more weakly it will be adsorbed on a polar surface
c) The greater the polarity of solute, more strongly it will be adsorbed on a polar surface
d) All of the mentioned option
Answer: c
Clarification: The greater the polarity of solute, more strongly it will be adsorbed on a polar surface.

5. The correct order of increasing strength of adsorption is ____________
a) Alkanes >> Esters >> Aldehydes >> Phenols >> Ketones
b) Aldehydes >> Phenols >> Ketones >> Esters >> Alkanes
c) Aldehydes >> Ketones >> Esters >> Alkanes >> Phenols
d) Alkanes >> Esters >> Ketones >> Aldehydes >> Phenols
Answer: d
Clarification: the correct order increasing strength of adsorption is: Alkanes >> Esters >> Ketones >> Aldehydes >> Phenols.

6. The components of the mixture in column chromatography are eluted in order of ____________
a) Increasing polarity and decreasing distribution ratio
b) Increasing polarity and increasing distribution ratio
c) Decreasing polarity and increasing distribution ratio
d) Decreasing polarity and decreasing distribution ratio
Answer: b
Clarification: The components of the mixture in column chromatography are eluted in order of increasing polarity and increasing distribution ratio.

7. The elution power of a solvent is determined by ____________
a) Its overall polarity
b) The polarity of the stationary phase
c) The nature of the sample components
d) All of the mentioned
Answer: d
Clarification: The elution power of a solvent is determined by its overall polarity, the polarity of the stationary phase and the nature of the sample components.

8. Which of the following is separated through column chromatography?
a) Chlorophyll and carotenoids
b) Inorganic cations or complexes
c) Sugar derivatives
d) Amino acids formed by hydrolysis of a protein molecule
Answer: a
Clarification: The main application of column chromatography is to separate plant pigment (Chlorophyll and carotenoids).

9. The mixture of petroleum ether and benzene is used in the elution ratio of ____________
a) 1 : 2
b) 1 : 5
c) 1 : 9
d) 1 : 12
Answer: c
Clarification: The mixture of petroleum ether and benzene is used in the elution ratio of 1:9 (V/V).

10. Chloroform fraction is eluted from the column by passing chloroform through the column which acts as ____________
a) Eluter
b) Eluant
c) Elution
d) None of the mentioned option
Answer: c
Clarification: Chloroform fraction is eluted from the column by passing chloroform through the column which acts as eluant. The eluate is the mobile phase leaving the column. The eluent is the solvent that carries the analyte.

250+ TOP MCQs on Mesomeric Effect and Answers

Engineering Chemistry online quiz focuses on “Mesomeric Effect”.

1. In mesomeric effect, the electrons are transferred from __________
a) A multiple bonds to an atom
b) A multiple bonds to a single covalent bond
c) An atom with a lone pair to the adjacent single covalent bond
d) All of the mentioned
Answer: d
Clarification: In the mesomeric effect, the electrons are transferred from multiple bonds to an atom, a multiple bond to a single covalent bond and an atom with the lone pair to the adjacent single covalent bond.

2. Which of the following is a resonance effect?
a) Inductive effect
b) Electromeric effect
c) Mesomeric effect
d) Inductomeric effect
Answer: c
Clarification: Mesomeric effect is also known as the resonance effect. The mesomeric effect is a permanent effect and operates in compounds containing at least one double bond.

3. The phenomenon in which 2 or more structures, involving identical position of atoms can be written for a particular molecule, is called __________
a) Conjugation
b) Resonance
c) Hyper conjugation
d) Vibration
Answer: b
Clarification: The phenomenon in which 2 or more structures, involving the identical position of atoms can be written for a particular molecule, is called resonance. The mesomeric effect is a permanent effect and operates in compounds containing at least one double bond.

4. Select the incorrect option from the following option.
a) Resonating structures have a real existence
b) The actual structure lies between various possible resonating structures
c) Resonating structures are useful as they allow us to describe molecules
d) None of the mentioned
Answer: a
Clarification: Resonating structures have no real existence. All the other options are correct. The actual structure lies between various possible resonating structures, resonating structures are useful as they allow us to describe molecules.

5. The resonance energy is defined as a difference in energy between __________
a) Two consecutive resonating structures
b) Resonance hybrid and most unstable resonating structure
c) Resonance hybrid and most stable resonating structure
d) First and last resonating structures
Answer: c
Clarification: The resonance energy is defined as a difference in energy between resonance hybrid and most stable resonating structure. The resonance energy of a compound is a measure of the extra stability of the conjugated system compared to the corresponding number of isolated double bonds.

6. Which of the following is an application of the mesomeric effect?
a) Dipole moment
b) Strength of acids and bases
c) Bond length
d) All of the mentioned
Answer: d
Clarification: Dipole moment, strength of acids and bases and bond length are some of the applications of the mesomeric effect.

7. Dipole moment of CH3-CH2-Cl > CH2=CH-Cl.
a) True
b) False
Answer: a
Clarification: Dipole moment of CH3-CH2-Cl > CH2=CH-Cl. This is due to resonance in vinyl chloride.

8. Select the correct statement from the following option.
a) Benzene ring has two different types of bond length for single and double bonds
b) All the bond length in benzene ring is equal due to hyperconjugation
c) All the bond length in benzene ring is equal due to resonance
d) All of the mentioned
Answer: c
Clarification: All the bond length in the benzene ring is equal due to resonance. All the bond lengths are equal in benzene ring i.e. double bond as well as single bond due to resonance.

9. Greater the number of resonating structures for a given intermediate __________
a) Less will be its stability
b) More will be its stability
c) It will not affect its stability
d) None of the mentioned
Answer: b
Clarification: Greater the number of resonating structures for a given intermediate, more will be its stability. More resonating structure increases stability.

10. Phenyl group show __________
a) (+M) effect
b) (+E) effect
c) (+I) effect
d) (-M) effect
Answer: d
Clarification: Phenyl group show (-M) effect. The phenyl group or phenyl ring is a cyclic group of atoms with the formula C6H5.

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