chemical engineering MCQs – Page 112

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 Review each marked answer and report any item that may be outdated or unclear.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
2221. For continuous drying of granular or crystalline material, the dryer used is the _______________ dryer?
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A. Tunnel

B. None of these

C. Rotary

D. Tray

2222. In a distillation operation, what is the effect of the temperature of the reflux stream (given below) on the condenser and reboiler loads? Reflux conditions: (i) Reflux stream is completely liquid and is at its bubble point. (ii) Reflux stream is below its bubble point ?
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A. Condenser and reboiler loads are the same in both the cases

B. Reboiler load is the same in both the cases but condenser load is higher in case (ii)

C. Condenser load is the same in both the cases but reboiler load is higher in case (ii)

D. Both condenser and reboiler loads are higher in case (ii) as compared to case (i)
2223. The diffusivity D. in a binary gas mixture is related to the temperature (T) as________________________?
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A. D ? T1.5

B. D ? T2

C. D ? T

D. D ? T0.5

2224. _____________ is used as an entrainer for the separation of acetic acid-water mixture by distillation?
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A. Benzol

B. Hexane

C. Furfural

D. Butyl acetate
2225. Molecular diffusion is caused by the________________?
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A. Potential energy of the molecules

B. Activation energy of the molecules

C. Transfer of molecules from low concentration to high concentration region

D. Thermal energy of the molecules
2226. The operating line for an absorber is curved, when plotted in terms of _______________________?
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A. Mass fractions

B. Partial pressure

C. Mole ratios

D. Mole fractions

2227. Which of the following mixtures does not form an azeotrope at atmospheric pressure ?
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A. Water-alcohol

B. Methyl alcohol-acetone

C. Butyl acetate-water

D. None of these
2228. If mass diffusivity in a mixture is equal to the thermal diffusivity, then the Lewis number is____________________
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A. 1

B. 0

C. 1
2229. Heat load in a cooling tower______________________?
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A. Means the amount of heat thrown away (KCal/hr.) by the cooling tower

B. Is equal to the number of kg, of water circulated times the cooling range

C. Both A. & B.

D. Neither A. nor B.

2230. Which of the following is an undesirable property for an absorbing solvent ?
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A. Low freezing point

B. None of these

C. Low vapour pressure

D. Low velocity

2231. In case of gases, the binary diffusivity is proportional to (where, P = pressure) ?
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A. ?P

B. 1/?P

C. P

D. 1/P
2232. Diffusion in concentrated solutions differs from that in dilute solutions, because of the change in the _______________ with the concentration of the solution?
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A. Degree of ideality

B. Viscosity

C. Both A & B

D. Neither A nor B

2233. Calcium ammonium nitrate (a fertiliser) is dried in a _________________ dryer?
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A. Tunnel

B. Rotary

C. Vacuum

D. Tray

2234. The rate of mass transfer is not dependent upon the______________________?
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A. Degree of dispersion of one fluid in the other

B. Interfacial surface exposed between the phases

C. Both A. & B.

D. None of these
2235. Which of the following is the most suitable for extraction in a system having very low density difference ?
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A. strong>. Pulsed extractor

B. Mixer-settler extractor

C. Centrifugal extractor

D. Packed extraction tower

2236. In distillation columns, the number of bubble caps per tray primarily depends upon the_______________________?
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A. Allowable gas velocity

B. Allowable liquid velocity

C. Feed composition

D. Allowable gas and liquid velocities
2237. Channelling in a packed tower results from the_____________________?
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A. High pressure drop

B. Maldistribution of liquid

C. Non-uniformity of packing

D. Both B. and C.
2238. Pick out the wrong statement pertaining to the rotary dryer ?
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A. instant. The best performance for rotary drier is obtained, when the hold up is in the range

B. Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute

C. Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at

D. n through the current of hot air/gases. It extends from the wall to a distance which is about

E. Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it

F. Rotary dryer is suitable for drying sticky material
2239. For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as___________________?
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A. Re0.53

B. Re

C. Re0.33

D. Re0.83
2240. Which of the following employs an accessory known as drift eliminator ?
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A. Multiple effect evaporator

B. Rotary dryer

C. Mechanical draft cooling tower

D. Rotating disc contactor