chemical engineering MCQs – Page 121

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs

6001. Function of secondary air in pulverised coal firing is to_________________?
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A. Reduce primary air requirement

B. Dry the coal

C. Transport the coal to the burner

D. Ensure efficient burning of coal around the burner

6002. Refractory castables are used for__________________?
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A. Minimising the number of joints in the structure

B. Producing monolithic linings

C. All A., B. and C.

D. Patch work

6003. Calorific value of pitch creosote mixture (PCM) i.e., C.T.F.-200 is about________________?
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A. 25000 kcal/kg

B. 8800 kcal/kg

C. 8800 kcal/m3

D. Same as that of coal middling

6004. Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of__________________?
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A. Too much air for combustion

B. Pulverised coal in boilers

C. Less air for combustion

D. Correct amount of air for combustion

6005. Firing of refractory brick is done to __________________?
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A. Develop stable mineral forms in them

B. duct

C. All A., B. and C.

D. Dehydrate the dried refractory

E. Form ceramic bonds necessary for development of high crushing strength in the finished

6006. Which one expands on heating ?
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A. Silica bricks

B. Fireclay bricks

C. Both A. & B.

D. Neither A. nor B.

6007. Of the total tar present in raw coke oven gas, the tar recovered in primary cooler is about _______________ percent?
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A. 25

B. 5

C. 55

D. 75

6008. ____________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold?
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A. High density

B. High thermal conductivity

C. Low porosity

D. Non-wetting characteristics

6009. Thermal spalling mainly occurs during _____________ of furnaces?
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A. Cooling down

B. Warming up

C. Both A. & B.

D. Neither A. nor B.

6010. Coal tar fuel 200 (CTF 200) is a mixture of __________________?
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A. Light oil and pitch

B. Anthracene and crecosote oil

C. Pitch and creosote oil

D. Solar oil and pitch

6011. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3), while the C.V. is same on weight basis (i.e., kcal/kg) ?
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A. Propane and acetylene

B. B.F. gas and coke oven gas

C. Sewage gas and gobar gas

D. Propane and LPG

6012. Stokes equation is valid in the Reynolds number range__________________?
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A. 0.1 to 2

B. 10 to 100

C. 2 to 10

D. 0.01 to 0.1

6013. Silica bricks are never used for lining the____________________?
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A. Roof of open hearth furnace

B. Beehive coke ovens

C. Dome of blast furnace stoves

D. By-product coke ovens

6014. Which of the following is the most common pump for pumping either raw sewage or sludge ?
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A. Electromagnetic pump

B. Centrifugal pump

C. Reciprocating pump

D. Gear pump

6015. Silica refractories are not used in _________________?
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A. Beehive coke ovens

B. Dome and upper portion of B.F. stoves

C. Coke oven walls

D. Open hearth furnace roof

6016. In a/an _____________, the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure?
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A. Rotameter

B. Pitot tube

C. Venturimeter

D. Flow nozzle

6017. Use of higher percentage of lime for bonding silica bricks, reduces their__________________?
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A. Strength

B. Abrasion resistance

C. Both A. & B.

D. Neither A. nor B.

6018. The velocity for subsonic flow in a pipeline_______________?
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A. Decreases in the downstream direction

B. Increases in the downstream direction

C. Is independent of the area of flow

D. Is constant

6019. With increase in the alumina content, the refractoriness of high alumina refractories_______________?
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A. Increases

B. May increase or decrease

C. Decreases

D. Remain same

6020. Which form of silica has the highest specific gravity ?
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A. Cristobalite

B. Tridymite

C. Quartz

D. All have the same specific gravity

6021. For turbulent flow of an incompressible fluid through a pipe, the flow rate Q? is proportional to (? P)n, where ?P is the pressure drop. The value of exponent n is_________________?
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A. > 1

B. 1

C. < 1

D. 0

6022. Natural silica___________________?
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A. All A., B. and C.

B. Transforms to other allotropic forms i.e. Tridymite and Cristobalite involving very high

C. Is not stable at high temperature

D. Mainly contains quartz

E. ume changes

6023. The speed of a sound wave in a gas is analogous to the speed of ______________________?
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A. A disturbance travelling upstream in moving fluid

B. None of these

C. Flow in an open channel

D. An elementary wave in an open channel

6024. Actual lift of a pump is always less than the theoretical lift and is limited by the__________________________?
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A. Leakage & pressure decreasing at higher elevations

B. Specific gravity & temperature of the liquid

C. Frictional resistance through pipes, fittings & passages

D. All A., B. and C.

6025. Hot blast main (carrying air at 1000C) in blast furnace are lined with ______________ bricks?
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A. Zirconia

B. Magnesite

C. Fireclay

D. Silica

6026. Applicability of Bernoullis equation is limited to a/an _____________ fluid, that does not exchange shaft work with the surroundings?
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A. Incompressible

B. Non-viscous

C. Both A. and B.

D. Neither A. nor B.

6027. Fluid flow through a packed bed is represented by the ______________ equation?
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A. Erguns

B. None of these

C. Fannings

D. Hagen-Poiseuilles

6028. Fireclay bricks are used in the__________________?
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A. Outer lining of L.D. converter

B. Hearth bottom of blast furnace

C. Coke oven walls

D. Coke ovens regenerator

6029. Roof of a basic electric furnace is made of _____________ bricks?
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A. Superduty fireclay

B. Chromite

C. Silica

D. None of these

6030. What is the maximum theoretical suction lift (metres) of a reciprocating pump ?
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A. 10

B. 50

C. 100

D. 5

6031. Mullite is chemically represented by_________________?
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A. 3Al2O3. 2SiO2

B. Al2O3. SiO2

C. Al2O3. 2SiO2

D. 2Al2O3. 3SiO2

6032. The pressure co-efficient is the ratio of pressure forces to ______________ forces?
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A. Inertial

B. Viscous

C. Surface tension

D. Gravity

6033. Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?
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A. f1 < f2

B. Data not sufficient to relate f1 & f2

C. f1 = f2

D. f1 > f2

6034. Cold crushing strength of a refractory does not depend upon its ____________________?
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A. Shape

B. Composition

C. Firing temperature

D. Texture

6035. In a dry packed bed, the pressure drop will be changed by increasing the flow rate as__________________?
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A. V1.8

B. V

C. V-1

D. V-0.8

6036. Which of the following is not a dimension-less parameter ?
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A. Kinematic viscosity

B. Pressure-co-efficient

C. Froude number

D. Weber number

6037. In magnetic flow meters, voltage generation is________________?
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A. Due to the motion of conducting fluid through an externally generated uniform field

B. Proportional to the fluid velocity

C. Both A. and B.

D. Neither A. nor B.

6038. Tar dolomite bricks are used in the_________________?
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A. Electric furnaces

B. All A., B. and C.

C. Basic open hearth furnace

D. Basic Bessemer converter

6039. Fanning friction factor equation applies to the _____________ fluid flow?
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A. Non-isothermal condition of

B. Compressible

C. Both A. and B.

D. Neither A. nor B.

6040. Which of the following is most prone to pulsating discharge flow ?
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A. Gear pump

B. Centrifugal pump

C. Axial flow pump

D. Reciprocating pump

6041. Cold crushing strength of refractories depends upon its_________________?
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A. All A., B. and C.

B. Firing temperature

C. Composition

D. Texture

6042. Refractory bricks having lower porosity have_________________________?
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A. Low thermal conductivity

B. Greater strength

C. Low heat capacity

D. High insulating properties

6043. Drag force on the float of a Rotameter is (where Q = flow rate of the)__________________?
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A. ? ?Q

B. ? Q

C. Constant

D. ? Q2

6044. Faster rate of drying of moulded refractories results in high _____________ of refractories?
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A. Green strength

B. Voids

C. Shrinkage

D. Both B. and C.

6045. Air vessel of a reciprocating pump is initially filled with___________________?
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A. Atmospheric air

B. Water

C. None of these

D. Compressed air

6046. Carbon refractory blocks ___________________?
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A. Are wetted by molten iron

B. Are acidic in nature

C. Are used in the hearth of blast furnace

D. All A., B. and C.

6047. Tar bonded dolomite bricks__________________?
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A. Are used in outer lining of L.D. converters

B. All A., B. and C.

C. Are stored under controlled temperature & humidity to avoid hydration

D. Have poorer hydration resistance than pitch bonded bricks

6048. Pressure drop for turbulent fluid flow through a circular pipe is given by_________________?
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A. 64/Re

B. 32?LV/gc.D2

C. 4f (L/D) (v2/2gc). ?

D. f (L/D) (v2/2gc). ?

6049. Reynolds number for flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around________________?
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A. 100

B. 1000

C. 2000

D. 10

6050. Bernoullis equation is not applicable, when the flow is___________________?
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A. Irrotational

B. Viscous

C. All A., B. & C.

D. Incompressible

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