Category: Engineering Chemistry Objective Questions

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

1. What is the time required for the formation of young brown coals?
a) 10⁷ years
b) 3×10⁸ years
c) 3×10⁹ years
d) 10¹⁰ years
Answer: a
Clarification: For the formation of matured coals (bituminous and anthracite) 3×10⁸ years are required where as for the young brown coal (peat and lignite) 10⁷ years are required. The temperature for the formation of coal is greater than 300^o.

2. Which of the following substance is transformed to coal in its early stage?
a) Animal debris
b) Bacteria
c) Vegetable debris
d) Non-living compounds
Answer: c
Clarification: Vegetable debris is formed by the microbial degradation of dead plants. The bacteria act as an agent is the transformation of vegetable debris into coal and animal debris are converted into petroleum products.

3. How is peat directly converted into anthracite by the process of parallel evolution (Hilt’s law)?
a) By maintaining the acid conditions
b) By the process of consolidation and dewatering
c) By the aerobic decay of peat
d) By continuous eliminations of H₂ gas
Answer: d
Clarification: When there is continuous elimination of H₂ gas, it creates an anaerobic condition due to which there is loss O₂ which creates anthracite directly. For aerobic decay, under sedimentary rocks lignite and bituminous coal are formed under different conditions.

4. Which of the following coal contains alternative dull and laminated layers?
a) Cannel coals
b) Banded coals
c) Splint coals
d) Bog-head coals
Answer: b
Clarification: Banded coals are bituminous coals that are identified as vitrain, clarain, durain and fusain. Splint coals are black in colour which burns freely without swelling and cannel coals consist of a greasy lustre.

5. Proximate analysis includes the estimation of ash, carbon, hydrogen, sulphur, nitrogen and oxygen.
a) True
b) False
Answer: b
Clarification: Proximate analysis is used for the determination of moisture, volatile matter, ash and fixed carbon. Ultimate analysis is used for the following given purposes.

6. Why is the high percentage of moisture undesirable for coal?
a) It increases the rate of combustion
b) It increases the cost of the coal
c) It reduces the calorific value of coal
d) It decreases its ignition temperature
Answer: c
Clarification: Moisture acts as a barrier in combustion which consequently decreases the calorific value of the coal. Moisture can be removed by drying the coal and the transportation of coal becomes easy.

7. Which of the following component is not a constituent of coal?
a) Moisture
b) Ash
c) Fixed carbon
d) Volatile matter
Answer: d
Clarification: Volatile matter consists of a complex mixture of gaseous and liquid products resulting from the thermal decomposition of the coal. Fixed carbon and ash are constituents of coal where as volatile matter is obtained after the decomposition of coal.

8. For manufacturing of metallurgical coke which of the following properties a coal should have?
a) Low volatile matter and high fixed carbon content
b) High volatile matter and high fixed carbon content
c) High volatile matter and low fixed carbon content
d) Low volatile matter and low fixed carbon content
Answer: a
Clarification: Coal having low volatile matter burn with a short flame and have a good heating value due to which it is preferred and high fixed carbon content helps to burn a coal completely. High volatile matter produces long flames and has a low heating value.

9. Ashes with fusion temperature above than 1430^oC are called as ___________
a) Fixed ash
b) Free ash
c) Refractory ash
d) Fusible ash
Answer: c
Clarification: The ash which is present within the mass of coal is called as fixed ash. Fusible ash is the ash that has a fusible temperature less than 1200^oC. Free ash can be removed by washing of coal.

10. At what temperature should the coal be heated so as to determine the moisture content of coal?
a) 90-100^oC
b) 145-155^oC
c) 125-140^oC
d) 105-110^oC
Answer: d
Clarification: Moisture is generally determined by heating a known quantity of air-dried coal to 105-110^oC for one hour so as to get an exact value of the percentile of moisture. The loss of weight in coal determines the percentile of moisture in the coal. If the temperature is shifted from this position it will affect the percentile of oxygen.

Engineering Chemistry Questions & Answers for Exams focuses on “Synthetic Gasoline from Non-Petroleum Sources – 2”.

1. Which type of coal is used in Bergius process?
a) Anthracite coal
b) Steam coal
c) Pulverised coal
d) Gas coal
Answer: d
Clarification: Bergius process is used to produce synthetic gasoline form low ash pulverised coal. This coal is finely divided into powder and is converted into a paste.

2. Which substance is mixed with the pulverised coal in the Bergius process?
a) Sulphuric acid
b) Heavy oil and catalyst
c) Heavy oil
d) Catalyst
Answer: b
Clarification: The paste of pulverised coal is mixed with a heavy oil and a catalyst. Nickel oleate is used as a catalyst in this process. This mixture is then sent to a converter.

3. At what temperature does the Bergius process is carried out?
a) 200-300 ⁰C
b) 700-800 ⁰C
c) 350-500 ⁰C
d) 0-150 ⁰C
Answer: c
Clarification: The temperature of converter is set to about 350-500 ⁰C and a pressure of about 200-250 atmospheres where the paste of coal meets hydrogen. The Fischer-Tropsch process is carried out at 200-300 ⁰C.

4. Which product is obtained from the converter in the Bergius process?
a) Hydrocarbons
b) Olefins
c) Fuel oil
d) Gasoline
Answer: a
Clarification: The combination of hydrogen with the carbon framework of the coal yields various hydrocarbons from wax to gases. The high molecular weight hydrocarbons are decomposed further at the high temperature prevailing in the converter giving lower hydrocarbons.

5. Same catalyst is used for production of oil in the Bergius process as used in the production of hydrocarbons.
a) True
b) False
Answer: b
Clarification: For production of gasoline, oils produced in the first stage of the process are subjected to further hydrogenation in the presence of different catalyst. Nickel oleate is not used for this process.

6. Which compounds are rich in gasoline obtained from the Bergius process?
a) Tetraethyl lead
b) Ethanol
c) Olefins
d) Aromatic compounds
Answer: d
Clarification: The gasoline obtained from the Bergius process is rich in aromatic and branched-chain hydrocarbons. Tetraethyl lead is an anti-knocking agent which is used for increasing the octane number.

7. What happens to the middle oil fraction in the Bergius process?
a) The oil is converted into olefins
b) The oil is converter into paraffin
c) The oil is converted into gasoline
d) The oil is converted into hydrocarbons
Answer: c
Clarification: The middle oil fraction is subjected to hydrogen in the presence of a catalyst to produce gasoline. Same process is carried out in the top fraction of the reactor. The heavy oil fraction is recycled to make a paste with a fresh batch of coal powder.

8. Which undesirable compound is present in gasoline?
a) Sulphur compounds
b) Phosphorous compounds
c) Chloride compounds
d) Magnesium compounds
Answer: a
Clarification: The gasoline obtained by any process contains some sulphur compounds and unsaturated hydrocarbons, which get oxidized and polymerised to gums and sludge’s. Hence it has to be refined by chemical processes.

9. How much percentile of sulphuric acid is treated with gasoline for the removal of its impurities?
a) 99 %
b) 60 %
c) 80 %
d) 40 %
Answer: c
Clarification: The impure gasoline is treated with cold 80 % sulphuric acid. This does not react with paraffin, naphthenes and aromatic compounds. It reacts with unsaturated hydrocarbons to produce alcohols and ethers.

10. Removal of gaseous impurities like methane, ethane, propane and butane from gasoline is called as _____________________
a) Stabilization of gasoline
b) Sweetening of gasoline
c) Doping of gasoline
d) Blending of gasoline
Answer: a
Clarification: The stabilization of gasoline is achieved by passing the impure gasoline into a fractionating tower having 49 plates. The lower plates are heated by steam, while the gasoline is introduced near the upper plates.

exam questions on Engineering Chemistry,

Engineering Chemistry Quiz focuses on “Calgon Conditioning”.

1. What is Calgon?
a) Potassium hexa meta sulphate
b) Magnesium hexa meta phosphate
c) Sodium hexa meta phosphate
d) Calcium hexa meta sulphate
Answer: c
Clarification: Calgon is sodium hexa meta phosphate. Calgon prevents limescale build-up in washing machines all over the world to protect the heating element, pipes and drum of the machines.

2. Calgon is added to boiler water to prevent ___________
a) Foaming
b) Sludge and scale formation
c) Priming
d) Corrosion
Answer: b
Clarification: Calgon is added to boiler water to prevent sludge and scale formation. Calgon prevents limescale build-up in washing machines all over the world to protect the heating element, pipes and drum of the machines.

3. Calgon converts the scale forming impurity like CaSO₄ into ___________
a) Soluble complex compound
b) Insoluble complex compound
c) Soluble acids
d) Insoluble acids
Answer: a
Clarification: Calgon converts the scale forming impurity like CaSO₄ into soluble complex compound which are harmless to boiler.

4. The quantity of calgon to be added to prevent scale and sludge formation is ___________
a) 10-20 ppm
b) 30-50 ppm
c) 0.005-0.1 ppm
d) 0.5-5 ppm
Answer: d
Clarification: The quantity of calgon to be added to prevent scale and sludge formation is 0.5-5 ppm. It is used in small quantity.

5. At high temperature and pressure, calgon is converted into sodium ortho-phosphate which reacts with ____________ salts.
a) Magnesium
b) Calcium
c) Sodium
d) Potassium
Answer: b
Clarification: At high temperature and pressure, calgon is converted into sodium orthophosphate which reacts with calcium salts to form calcium ortho-phosphate.

6. Calcium ortho-phosphate appears as loose sludge and thus can be removed by blow-down operation.
a) True
b) False
Answer: a
Clarification: Calcium orthophosphate appears as loose sludge and thus can be removed by blow-down operation. It is formed by the reaction of sodium ortho-phosphate with calcium salts.

7. Calgon conditioning is not applicable for the prevention of ___________
a) Iron oxide only
b) Copper depositions only
c) Sulphurdioxide only
d) Iron oxide and copper depositions
Answer: d
Clarification: Calgon conditioning is not applicable to the prevention of iron oxide and copper depositions. Calgon prevents limescale build-up in washing machines all over the world to protect the heating element, pipes and drum of the machines.

8. Iron oxide and copper depositions can be prevented by adding ___________ to the boiler water.
a) Calgon
b) Carbonate
c) EDTA
d) EBT
Answer: c
Clarification: Iron oxide and copper depositions can be prevented by adding EDTA to the boiler water. Ethylenediaminetetraacetic acid (EDTA), is an amino poly-carboxylic acid and a colorless and a water-soluble solid.

9. Carbonate conditioning is not done in high pressure boilers because it may lead to caustic embrittlement.
a) True
b) False
Answer: a
Clarification: Carbonate conditioning is not done in high pressure boilers because it may lead to caustic embrittlement. Caustic embrittlement is the phenomenon in which the material of a boiler becomes brittle due to the accumulation of caustic substances.

10. Which of the following is not used in colloidal conditioning?
a) Kerosene
b) Tannin
c) Agar-agar
d) Vinegar
Answer: d
Clarification: Kerosene, tannin and agar-agar are used in colloidal conditioning. Vinegar is not used for this purpose.

areas of Engineering Chemistry for Quizzes,

Engineering Chemistry Multiple Choice Questions on “Lubricants”.

1. Lubrication is necessary to protect wear and tear caused due to _______________
a) Electrostatic force
b) Gravitational force
c) Frictional force
d) Magnetic force
Answer: c
Clarification: Lubrication is necessary to protect wear and tear caused due to frictional force. Electrostatic, gravitational and magnetic forces do not cause wear and tear.

2. Lubricant act as a coolant to carry away heat.
a) True
b) False
Answer: a
Clarification: Lubricant act as a coolant to carry away heat and is generally used in refrigerators and air conditioners.

3. Select the incorrect statement from the following option.
a) Lubricant keeps out dirt
b) Lubricant act as a seal
c) Lubricant transmit fluid power
d) Lubricant enhance corrosion
Answer: d
Clarification: Lubricants prevents corrosion. It does not act as a seal or remove dirt and also not transmit fluid power.

4. The viscosity of petroleum oil for hydraulic lifts is ____________
a) High
b) Low
c) Moderate
d) Very high
Answer: b
Clarification: The viscosity of petroleum oil for hydraulic lifts is low as it makes it less dense and easier to lift up while carrying the operation.

5. The science of friction, lubrication and wear is called ____________
a) Endiology
b) Geology
c) Tribology
d) Morphology
Answer: c
Clarification: The science of friction, lubrication and wear is called tribology. Morphology and Geology relates to the science of Earth’s crust and rock structure.

6. On increasing the lubrication, the efficiency of the machine ____________
a) Increases
b) Decreases
c) Remain same
d) Does not get affected
Answer: a
Clarification: On increasing the lubrication, the efficiency of the machine increases as it increases the speed of the operations and causes less wear and tear.

7. The stearate ion has a ________ carbons long hydrocarbon chain.
a) 17
b) 19
c) 21
d) 23
Answer: a
Clarification: The stearate ion has a 17 carbons long hydrocarbon chain, which is hydrophobic in nature.