Category: Engineering Chemistry Objective Questions

Engineering Chemistry Multiple Choice Questions on “Carbonization of Coal”.

1. All types of coals can be converted into coke.
a) True
b) False
Answer: b
Clarification: All types of coals cannot be converted into coke. Only that coal which has a tendency to soften, swell and stick together during strong heating in absence of air can be coked.

2. The process of converting coal into coke is called ______
a) Coking
b) Carbonization
c) Decarbonization
d) Isomerization
Answer: b
Clarification: The process of converting coal into coke is called carbonization. When coking coal is heated in absence of air, porous, strong and hard residue left is called coke.

3. Depending on the behaviour of the coal, when it is heated in the absence of air, it can be categorized into ______ categories.
a) 2
b) 3
c) 4
d) 5
Answer: a
Clarification: Depending on the behaviour of the coal, when it is heated in the absence of air, it can be categorized into 2 categories, Coking and Non-coking coals.

4. Which coals are suitable for metallurgical purposes?
a) Coking
b) Carburized
c) Non-coking
d) Decarburized
Answer: a
Clarification: Coking coals are suitable for metallurgical purposes because they are quite strong and not crushed under the weight of ore.

5. Only bituminous type of coal can be coked.
a) True
b) False
Answer: a
Clarification: Only that coal which has tendency to soften, swell and stick together during strong heating in absence of air can be coked. This property is found only in the bituminous type of coal.

6. Caking coal with ______ content are used for gas manufacturer.
a) high volatile matter
b) low volatile matter
c) high ash content
d) high moisture content
Answer: a
Clarification: Caking coal with high volatile matter content are used for gas manufacture whereas caking coal with low moisture matter content is used for the manufacturing of metallurgical coke.

7. Practically, coking coals are blended with ______
a) caking coals
b) non-caking coals
c) non-coking coals
d) lignite
Answer: b
Clarification: Coking coals are blended with non-caking coals since it helps in increasing the rate of carbonization and producing good quality coke from non-caking coal.

8. Select the correct statement among the given below.
a) All coking coals are caking but not all caking coals are coking
b) All caking coals are coking but not all coking coals are caking
c) Coking and caking are the same types of coals
d) All types of coals can be coked
Answer: a
Clarification: All coking coals are caking but not all caking coals are coking.Only that coal which has a tendency to soften, swell and stick together during strong heating in absence of air can be coked.

9. Coals which become soft, plastic and fuse together to form large coherent masses are called ______
a) caking coals
b) non-caking coals
c) non-coking coals
d) pulverized coal
Answer: a
Clarification: Coals which becomes soft, plastic and fuse together to form large coherent masses are called caking coals. Coals which undergo no fusing affects are called non-coking coals. Coking coals give hard, porous and strong residue after heating in absence of air.

10. When a coking coal is burnt in absent of air, hard, strong and porous residue left is called as _____
a) Coke
b) Ash
c) Caking coal
d) Non-coking coal
Answer: a
Clarification: When a coking coal is burnt in absent of air, hard, strong and porous residue left is called coke. Coke is white, lustrous, dense, porous and coherent mass.

Engineering Chemistry Multiple Choice Questions on “Gaseous Fuels – 2”.

1. Which of the following undesirable component is removed from natural gas?
a) NO₂
b) SO₂
c) N₂
d) SO₃
Answer: c
Clarification: The natural gas is processed to remove nitrogen, since it decrease the rate of combustion. Other undesirable products such as water, grit and dust, CO₂and H₂S are removed from natural gas.

2. Which of the following product can be recovered from natural gas?
a) Phosphorous
b) Magnesium
c) Boron
d) Sulphur
Answer: d
Clarification: Sulphur is recovered from H₂S containing natural gas. The reaction involved are:
2H₂S + 3O₂ → 2SO₂ + 2H₂O
2 H₂S + SO₂ → 3S + 2H₂O.

3. In which region of India maximum natural gas is obtained?
a) Assam
b) Mumbai high
c) Chennai
d) Trivandrum
Answer: a
Clarification: India’s proved reserves of natural gas are of the order of 40 km³. Most of the natural gas lies in Assam and Gujrat. Mumbai high has less reserves of natural gas.

4. Which of the following gas can be used as natural gas?
a) Phosgene
b) Syngas
c) Sulphur di-oxide
d) Carbon di-oxide
Answer: b
Clarification: Syngas is a low and medium-heat gas produced from coal and can be converted into high-heat content gas similar to natural gas. This natural gas produced is also called as substitute natural gas (SNG).

5. At what temperature does the substitute natural gas is prepared?
a) 1200-1650 ⁰C
b) 100-400 ⁰C
c) 500-800 ⁰C
d) More than 1700 ⁰C
Answer: a
Clarification: The operating pressure in the gasifier, depending upon the process, can be atmospheric to over 6.9 Mpa. The temperature cane vary from 800 ⁰C to about 1650 ⁰C.

6. In oil gasification, at what ratio does naphtha and water are mixed?
a) 2:1
b) 1:2
c) 3:4
d) 4:3
Answer: b
Clarification: Naphtha and other oils can be converted to SNG. The process uses a mixture of naphtha and steam in the ratio of 1:2 and then gasify it. The gas produced is methanated by the reaction of carbon-dioxides with the hydrogen present.

7. Coke-oven gas has a higher calorific value than the coal gas.
a) True
b) False
Answer: b
Clarification: Coal gas has slightly higher calorific value than the coke-oven gas. Coal gas is manufactured by heating high volatile matter coal taken in silica retorts to about 1350 ⁰C.

8. During the manufacture of coke-oven gas, which of the following is obtained as a by-product?
a) Volatile matter
b) Metallurgical coke
c) Ash content
d) Gas
Answer: d
Clarification: Coke-oven gas is made by heating coking coal in coke-ovens, in which metallurgical coke is obtained as the main product and gas is obtained as by-product. In the manufacture of coal gas, gas is obtained as main product.

9. Which of the following compound is dissolved in oil used in the manufacture of coal gas?
a) Benzol
b) Ethylene
c) Sodium Chloride
d) Tartaric acid
Answer: a
Clarification: Benzol, toluene and other aromatic compounds are dissolved in the creosote oil which is used in the manufacturing of coal gas. The benzol present in the gas produced can be recovered by passing through active charcoal and silica gel.

10. Which of the following oil is used in preparation of oil gas?
a) Lubricating oil
b) Naphtha
c) Kerosene oil
d) Coconut oil
Answer: c
Clarification: Oil gas consists of a mixture of hydrocarbons. It is prepared by cracking of kerosene oil. Naphtha is used for the production of substitute natural gas.

Engineering Chemistry Assessment Questions and Answers focuses on “Protective Measures Against Corrosion”.

1. Which of the following method is adopted for preventing corrosion by acids?
a) Deaeration
b) Removal by using ion-exchange resin
c) Neutralisation with lime
d) Dehumidification
Answer: c
Clarification: Neutralisation with lime is done for preventing corrosion by acids. Lime is a calcium-containing inorganic material in which carbonates, oxides and hydroxides predominate.

2. Which of the following method is adopted for preventing corrosion by salts?
a) Deaeration
b) Removal by using ion-exchange resin
c) Neutralisation with lime
d) Dehumidification
Answer: b
Clarification: To prevent corrosion by salts, they are removed by using ion-exchange resins. Through this Na⁺ and Cl^– gets separated.

3. Which of the following method is adopted for preventing corrosion by moisture?
a) Deaeration
b) Removal by using ion-exchange resin
c) Neutralisation with lime
d) Dehumidification
Answer: d
Clarification: To prevent corrosion by moisture, moisture from the air is removed by dehumidification using silica gel.

4. The organic or inorganic substances which when added to the environment are able to reduce the rate of corrosion are called ___________
a) Inhibitors
b) Stimulants
c) Insulators
d) Stipulator
Answer: a
Clarification: The organic or inorganic substances which when added to the environment are able to reduce the rate of corrosion are called inhibitors. They are also called corrosion inhibitors. A substance that prevents or decreases the rate of a chemical reaction is called a reaction inhibitor.

5. Which of the following readily sublime and form a protective layer on the metal surface?
a) Anodic inhibitor
b) Cathodic inhibitor
c) Volatile inhibitors
d) Non-volatile inhibitors
Answer: c
Clarification: Volatile or vapour-phase inhibitors readily sublime and form a protective layer on the metal surface.

6. Which of the following is not an anodic inhibitor?
a) Alkalis
b) Molybdates
c) Phosphates
d) Dicyclohexyl ammonium nitrile
Answer: d
Clarification: Alkalis, molybdates, phosphates and chromates are examples of anodic inhibitors.

7. The process by which Ta, Nb and Ti combine with carbon to form respective carbides and prevent corrosion is known as ___________
a) Passivation
b) Neutralisation
c) Inhibition
d) Stimulation
Answer: b
Clarification: The process by which Ta, Nb and Ti combine with carbon to form respective carbides and prevent corrosion is known as neutralisation. The pH of the neutralized solution depends on the acid strength of the reactants.

8. The process which lowers the content of sulphur and phosphorus in steels is known as ___________
a) Refining
b) Passivation
c) Inhibition
d) Stimulation
Answer: a
Clarification: The process which lowers the content of sulphur and phosphorus in steels is known as refining. It removes the impurities or unwanted elements from the steels.

9. Annealing is a heat treatment given to metals to ___________
a) Prevent dezincification
b) Remove the residual stresses
c) Lower the sulphur content
d) Form a protective layer
Answer: b
Clarification: Annealing is a heat treatment given to metals to remove the residual stresses. It involves heating a material to above its re-crystallization temperature, maintaining a suitable temperature, and then cooling.

10. Anodised oxide coatings are used for the protection of Al, Zn, Mg and their alloys from corrosion.
a) True
b) False
Answer: a
Clarification: Anodised oxide coatings are used for the protection of Al, Zn, Mg and their alloys from corrosion. They help in preventing corrosion by eliminating contact from the environment and air.

11. Which of the following statement is incorrect about the anodic coating?
a) Protects the metal from corrosion sacrificially
b) Base metal is not corroded
c) Example- coating of tin on iron
d) No negative consequence
Answer: c
Clarification: Example- coating of zinc on iron. All the other options are correct.

12. Organic coating is inert organic barrier whose protective value depends upon its impermeability to gases, salts and water.
a) True
b) False
Answer: a
Clarification: Organic coating is inert organic barrier whose protective value depends upon its impermeability to gases, salts and water. If the gases or salts are permeable to the organic coating, it will be useless. So the organic coating should be selected accordingly.

13. Electrochemical protection is ___________
a) Anodic protection
b) Sacrificial Anodic protection
c) Impressed current cathodic protection
d) Cathodic protection
Answer: d
Clarification: Electrochemical protection is cathodic protection(CP). It is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.

14. Magnesium is used in high resistivity electrolytes due to its ___________
a) Neutral potential
b) Most positive potential
c) Most negative potential
d) Zero potential
Answer: c
Clarification: Magnesium is used in high resistivity electrolytes due to its most negative potential. Magnesium has the highest negative potential according to the electrochemical series.

15. Which of the following metal is not used as a sacrificial anode?
a) Zinc
b) Copper
c) Magnesium
d) Aluminium
Answer: b
Clarification: Zinc, aluminium, magnesium are used as a sacrificial anode. Copper is not used as a sacrificial anode.

areas of Engineering Chemistry Assessment Questions,

Engineering Chemistry Multiple Choice Questions on “Colloids – 1”.

1. What is the size of colloidal particles?
a) 10-20 nm
b) More than 20 nm
c) Less than 10 nm
d) 30 to 50 nm
Answer: a
Clarification: Since colloidal are intermediate between powdered particles and suspension particles, they have a size in between these particles of about 10 to 20 nm. These are considered to be intermediate size of molecules.

2. Which of the following is a characteristic of a colloid?
a) It forms 2 layers with a solution
b) It forms turbid layers
c) It forms heterogeneous layer
d) It forms a homogeneous layer
Answer: b
Clarification: Since a colloidal particle does not from a single layer with solvents, the only possibility is to form a turbid layer where the solution is an intermediate between a miscible and immiscible solution.

3. Where does colloidal solution find application in?
a) In milk industries
b) In chromatic chemical industries
c) In crystallography
d) In textiles
Answer: a
Clarification: Since colloidal solutions can easily be emulsified with the help of emulsifying agents such as ethylene dichloride, it can find its major application in the field of dairy industries.

4. Calculate the size of the colloidal particle present in the mixture of fats and milk from the given data.
Amount of milk in litres: 20
Amount of fats in grams: 10
Time taken to mix the ingredients: 20 sec
a) 3
b) 6
c) 4
d) 61
Answer: c
Clarification: The size of the colloidal particles can be given by the formula
Size=amount of solvent x time/ amount of colloidal. Therefore in this problem, we can see that the size of the colloid is 20 x 20 / 10 = 4.

5. During an experiment, accidently iodine got mixed up with a biological sample of proteins and polys. Identify the smallest colloid that can be obtained during the process of separation.
a) Fats
b) Amino acids
c) Polys
d) R molecules
Answer: b
Clarification: Given that the solution of iodine got mixed up with milk sample, we know milk is already a colloidal solution of polymers like amino acids, proteins, fats, vitamins etc, the smallest among all these colloidal particles is amino acids.

6. Which of the following form of colloid is considered to be the strongest colloid?
a) Gel
b) Foam
c) Solid sol
d) Liquid sol
Answer: c
Clarification: We know that solid sol is the colloidal solution of a solid and a solid. Since there is a mixture of solid and solid, the bond between them is quite strong. Thus it is considered to be the strongest colloid.

7. Which of the following form of colloid is considered to be the lightest colloid?
a) Gaseous foam
b) Solid sol
c) Sol
d) Liquid sol
Answer: a
Clarification: We know that the gaseous foam is the colloidal solution of gaseous molecules and liquid. Thus there exists a lighter bond between the particles. Thus this is considered as the lightest colloid.

8. What is the size of normal an amino acid?
a) 1 to 2 nm
b) 2 to 3 nm
c) 4 to 5 nm
d) 2 to 5 nm
Answer: a
Clarification: We know that amino acids are nothing but single structure monomers of proteins. Thus they are visible only under an ultra microscope due to is an extreme small size in the range of nano meters. Their size ranges from 1 to 2 nm.

9. What is called a dispersion phase?
a) It is the main layer
b) It is the secondary layer in which the colloidal particles are dispersed
c) It is the secondary layer
d) It is the basic colloidal layer
Answer: b
Clarification: Since the colloidal particles require a layer in which it has to be dispersed, the dispersion phase is considered to be a second layer. The dispersion phase is generally a solvent.

10. What is called a dispersion medium?
a) It is where the dispersed phase settles
b) It is where the solute particles settle
c) It is where the dispersed phase is suspended
d) It is the primary medium
Answer: c
Clarification: Since to form a stable colloidal solution, the dispersed phase requires a stable solvent medium is required. This is the condition in which equilibrium is achieved. This medium is called a dispersion medium.

Engineering Chemistry Multiple Choice Questions on “E and Z Nomenclature of Geometric Isomers”.

1. What are Stereoisomers?
a) Isomers having a same molecular formula and same configuration
b) Isomers having a same molecular formula but different configuration
c) Isomers having a different molecular formula but the same configuration
d) Isomers having a different molecular formula and different configuration
Answer: b
Clarification: Stereoisomerism is exhibited by isomers having the 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
Answer: c
Clarification: 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
Answer: c
Clarification: Triply bonded compounds cannot exhibit geometrical isomerism as the -C=C- bond in these molecules 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
Answer: a
Clarification: 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
Answer: b
Clarification: A sawhorse projection can reveal staggered and eclipsed conformations.

6. Assign E or Z configuration to the given compound.

a) E-configuration
b) Z-configuration
c) S-configuration
d) R-configuration
Answer: a
Clarification: Trans-2-butene has two geometric isomers and this is E-configuration.

7. Which of the following compounds have Z-configuration?
a) _CH3^CH₃CH₂>C=CH_CH3
b) _H^Ph>C=CCOOH_Ph
c) _H2N^Cl>C=CCOOH_Br
d) _CH3^Ph>C=CCH₂CH_3Br
Answer: b
Clarification: 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
Answer: b
Clarification: 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
Answer: c
Clarification: 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
Answer: d
Clarification: In glyceraldehydes, the complete sequence of priority is –OH > CHO > -CH₂OH > -H.

Engineering Chemistry Question Bank focuses on “Fractional Distillation”

1. Fractional distillation is a process of separation of ____________
a) 2 miscible liquids
b) 2 immiscible liquids
c) 1 miscible and 1 immiscible liquid
d) None of the mentioned
Answer: a
Clarification: Fractional distillation is a process of separation of 2 immiscible liquids. Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize.

2. The difference in boiling point of 2 liquid in fractional distillation is ____________
a) Greater than 25 K
b) Less than 25 K
c) Equal to 25 K
d) None of the mentioned
Answer: b
Clarification: Difference in the boiling point of 2 liquid in fractional distillation is is less than 25 K. Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize.

3. A simple fractional tube is packed with ____________
a) Wooden beads
b) Plastic beads
c) Metal beads
d) Glass beads
Answer: d
Clarification: A simple fractional tube is packed with glass beads. The fractional distillation column is set up with the heat source at the bottom on the still pot.

4. Fractional distillation is different from distillation because of the presence of ____________
a) Fractionating column
b) Condenser
c) Distillation flask
d) Conical flask
Answer: a
Clarification: Fractional distillation is different from distillation because of the presence of fractionating column. A laboratory fractionating column is a piece of glassware used to separate vaporized mixtures of liquid compounds with close volatility.

5. The beads are provided in fractional column for ____________
a) Vapours to generate
b) Vapours to condense
c) Vapours to evaporate
d) All of the mentioned
Answer: b
Clarification: The beads are provided in fractional column for vapours to condense. The fractional distillation column is set up with the heat source at the bottom of the still pot.

6. Select the incorrect statement from the following options.
a) Fractionating columns are available in various design and size
b) Fractionating columns are available according to one fixed standard
c) A simple fractionating column is a tube packed with glass beads
d) Fractional distillation is the process of separation of different gases from air
Answer: b
Clarification: Fractionating columns are available in various design and sizes and not according to one fixed standard.

7. Which of the following gases cannot be separated from air using fractional distillation?
a) Argon
b) Oxygen
c) Helium
d) Nitrogen
Answer: c
Clarification: Helium gas cannot be separated from air using fractional distillation. Fractional distillation is used in air separation, producing liquid oxygen, liquid nitrogen, and highly concentrated argon.

8. Initially, the temperature at the top of the column is _______________ than at its bottom.
a) Greater
b) Lesser
c) Equal
d) None of the mentioned
Answer: b
Clarification: The temperature at the top of the column is lesser than at its bottom. The two major types of distillation columns used are tray and packing columns.

9. Which of the following is more suitable for fractional distillation process?
a) Oil bath
b) Water bath
c) Glycerine bath
d) None of the mentioned
Answer: a
Clarification: Oil bath is the most suitable option for the fractional distillation process. Vacuum distillation systems operate at reduced pressure, thereby lowering the boiling points of the materials. Anti-bumping granules, however, become ineffective at reduced pressures.

10. Number of steps required for the separation of two liquids in fractional distillation is _________
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: Number of steps required for the separation of two liquids in fractional distillation is 2. Vacuum distillation systems operate at reduced pressure, thereby lowering the boiling points of the materials. Anti-bumping granules, however, become ineffective at reduced pressures.

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