chemical engineering mass transfer MCQs – Page 8

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering mass transfer Mcqs
141. Molecular sieves are regenerated by heating to ______________ C?
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A. > 500

B. < 150

C. > 1000

D. 200-330
142. For ethanol-water system, the lowering of distillate quality from 95% to 92% will cause ____________________ plate requirement?
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A. Major decrease in the number of

B. None of these

C. No change in theoretical

D. Marginal decrease in the number of
143. In a gas-liquid absorption column, for obtaining the maximum absorption efficiency___________________?
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A. Liquid stream should be distributed uniformly

B. Gas stream should be distributed uniformly

C. Both gas as well as liquid streams should be distributed uniformly

D. By passing should be completely avoided

144. The value of L/mG ratio for economical absorption operation ranges from _____________________?
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A. 0.5 to 0.8

B. 0.8 to 1.2

C. 2.5 to 3.5

D. 1.25 to 2.0
145. Leaching of uranium ore and gold ore is done in________________________?
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A. None of these

B. Pachuca tanks

C. Centrifugal extractor

D. Bollman extractor

146. The relation among various mass transfer co-efficients (M.T.C) for ideal gases is given by (where, Kc & Km are M.T.C. for equimolar counter diffusion with concentration & mole fraction respectively as the driving force. and, Kp= M.T.C. for diffusion of a gas through a stagnant inert gas with pressure as driving force) ?
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A. Kc = Kp = Km

B. None of these

C. Kc = Kp . RT = Km . RT/p

D. Kc = Kp/RT = Km . RT/P

147. In triangular co-ordinates, the ternary composition point falls ___________________ of the triangle?
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A. In the corners

B. On the sides

C. Inside

D. None of these

148. During constant rate period, the rate of drying decreases with the______________________?
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A. Decrease in air temperature

B. Increase in air humidity

C. Both A. and B.

D. Neither A. nor B.

149. Swenson-Walker crystalliser is a __________________ unit ?
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A. Cooling (adiabatic)-cum-evaporation

B. Batch

C. Semi-batch

D. Continuous
150. What is the degree of freedom of an absorption process in which only one component is transferred between phases ?
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A. 2

B. 3

C. 4

D. 1

151. For the flow of gases through a capillary, with increase in temperature, the permeability __________________ as per Knudsen law?
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A. Increases

B. Either A. or B.; depends on the gas

C. Decreases

D. Remain same

152. Which of the following has the same dimension as mass diffusivity ?
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A. Momentum flux

B. Kinematic viscosity

C. Thermal diffusivity

D. Both B. and C.
153. Large quantity of silica gel is normally dried in a _________________ dryer?
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A. Rotary vacuum

B. Freeze

C. Tray

D. Through circulation
154. Ammonia present in the coke oven gas is removed by washing with___________________?
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A. Caustic solution

B. Dilute ammoniacal liquor

C. Dilute HCl

D. Ethanolamine

155. The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling ?
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A. Liquid side

B. Gas side

C. Interfacial

D. Both liquid and gas side

156. For a single component absorber, the operating line is straight only when plotted in term of ______________ units?
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A. Mole ratio

B. Partial pressure

C. Mole fraction

D. None of these

157. Which of the following is directly concerned with Psychrometry ?
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A. Galileo number

B. Lewis relationship

C. Dean number

D. Weber number

158. Steady state equimolal counter diffusion is encountered in_____________________?
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A. Absorption of NH3 from air by water

B. All liquid-solid diffusion systems

C. Separation of a binary mixture by distillation

D. All liquid-liquid diffusion systems

159. Drying of a wet solid under constant drying conditions means the exposure of the wet solid to the air of constant______________________?
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A. Humidity

B. All A., B. & C.

C. Velocity

D. Temperature

160. The cooling effect in a cooling tower cannot be increased by_____________________?
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A. Lowering the barometric pressure

B. Reducing the humidity of entering air

C. None of these

D. Increasing the air velocity over the wet surfaces