Competitive Chemical Engineering MCQs – Up To Date Mass Transfer MCQs
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Latest Chemical Engineering MCQs
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Latest Mass Transfer Mcqs
The most occurred mcqs of Mass Transfer in past papers. Past papers of Mass Transfer Mcqs. Past papers of Mass Transfer Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Mass Transfer Mcqs. The Important series of Mass Transfer Mcqs are given below:
Rotary dryers cannot handle _______________ materials ?
A. Dry
B. Free flowing
C. Sticky
D. Granular
Smoke is an example of ___________________?
A. Liquid dispersed in gas
B. Solid dispersed in gas
C. Solid dispersed in liquid
D. Gas dispersed in liquid
Batch tray dryers suffers from the disadvantage of______________________?
A. Non-uniform & low production rate
B. High maintenance cost
C. High labour cost & low heat economy
D. All ‘a’, ‘b’ & ‘c’
A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state ?
A. The top and bottom compositions are unchanged with and without total reflux
B. Reboiler load and condenser load are minimum
C. Composition of vapors and that of liquid do not vary throughout the column
D. The top and bottom compositions correspond to the maximum enrichment available
Heat sensitive materials with very high latent heat of vaporisation may be economically separated using__________________?
A. Liquid extraction
B. Evaporation
C. Distillation
D. Absorption
In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter ?
A. < 8 : 1
B. > 4 :1
C. > 8:1
D. < 6:1
Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around _____________ inches?
A. 60
B. 30
C. 5
D. 100
In the absorption of ammonia in water, the main resistance to absorption is by the _________________ phase?
A. Liquid
B. Gas
C. Both of the above
D. Neither of the above
During bottling of cold drinks (e.g. Pepsi), the main resistance to mass transfer for the absorption of carbon dioxide in water lies in the___________________?
A. Liquid-gas interface
B. Liquid film
C. Gas film
D. None of these
______________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction ?
A. Spray
B. Bubble
C. Packed
D. Tray
If the solubilities of different components (in a liquid-liquid extraction system) increase with rise in temperature, then the temperature above which they dissolve completely is known as the critical solution temperature (CST or consolute temperature). If solubilities increase with decrease in temperature, then CST is the temperature below which they dissolve completely. If a binary system has no critical solution temperature, it implies that___________________?
A. The system comprises of miscible liquids
B. The system comprises of partially miscible liquids
C. The system comprises of an azeotrope
D. On heating, a vapor phase will appear; while on cooling, a solid phase will appear
Leaching of coffee from coffee beans is done by___________________?
A. Hot water
B. Lime water
C. Hexane
D. Dilute H2SO4 (hot)
Desirable value of absorption factor in an absorber is___________________?
A. < 1
B. 1
C. > 1
D. 0.5
In case of a desorber (stripper), the________________?
A. Temperature remains unaffected
B. Operating line always lies below the equilibrium curve
C. Operating line always lies above the equilibrium curve
D. Temperature always increases
In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit) ?
A. Parallel
B. Straight
C. Both A. & B.
D. Neither A. nor B.
Make up water is required in a cooling tower to replace the water lost by___________________?
A. Drift
B. Evaporation
C. Blowdown and leakage
D. All A., B. and C.
The expression, ln(F/W) = ∫xF xW [dx/y* – x)] is_____________________?
A. Differential distillation equation
B. Slope of q-line in McCabe-Thiele method
C. For NtoG in absorption for dilute mixture
D. For relative volatility
Mass Transfer Mcqs
The diffusivity, DAB (for component A diffusing in B) is equal to the diffusivity DBA (for component B diffusing in A) for a binary mixture of________________?
A. Non-Newtonian liquids
B. Newtonian liquids
C. Ideal gases
D. Real gases
Molecular diffusion is caused by the________________?
A. Transfer of molecules from low concentration to high concentration region
B. Thermal energy of the molecules
C. Potential energy of the molecules
D. Activation energy of the molecules
Liquid diffusivity is of the order of _______________ cm2 /second?
A. 0.1
B. 0.01
C. 10-5 to 10-6
D. > 1
The overall mass transfer co-efficient for the absorption of SO2 in air with dilute NaOH solution can be increased substantially by___________________?
A. Increasing the gas film co-efficient
B. Increasing the total pressure
C. Increasing the liquid film co-efficient
D. Decreasing the total pressure
When the psychometric ratio is ______________ then the adiabatic saturation temperature and wet bulb temperature becomes equal?
A. 1
B. 0
C. 2
D. ∞
Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) ?
A. Increases pressure drop, decreases surface area
B. Increases pressure drop, increases surface area
C. Decreases pressure drop, increases surface area
D. Decreases pressure drop, decreases surface area
Fenske equation for determining the minimum number of theoretical stages in distillation column holds good, when the_________________?
A. Relative volatility is reasonably constant
B. Mixture (to be separated) shows positive deviation from ideality
C. Mixture (to be separated) shows negative deviation from ideality
D. Multi-component distillation is involved
Stefan’s law describes the mass transfer by________________?
A. Bulk flow
B. Diffusion
C. Both A. & B.
D. Neither A. nor B.
Flights in a rotary dryer are provided to________________?
A. Lift and shower the solids thus exposing it thoroughly to the drying action of the gas
B. Increase the residence time of the solid
C. Reduce the residence time of solid
D. None of these
The adiabatic saturation curve for a vapour-gas mixture is__________________?
A. Slightly concave downward
B. Slightly concave upward
C. Straight line
D. None of these
The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the ______________ temperature?
A. Wet bulb
B. Dew point
C. Dry bulb
D. None of these
At what value of reflux ratio, number of theoretical plates in a distillation column is minimum ?
A. 1
B. 0
C. ∞
D. < 1
With increase in solvent rate, the number of transfer units, NtoG, for a fixed degree of absorption from a fixed amount of gas________________?
A. Decreases linearly
B. Decreases
C. Increases
D. Remain unaffected
For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as___________________?
A. Re0.53
B. Re0.33
C. Re0.83
D. Re
The vapour pressure exerted by the moisture contained in a wet solid depends upon the____________________?
A. Temperature
B. Nature of the moisture
C. Nature of the solid
D. All A., B. and C.
Petroleum Refinery Engineering Mcqs
Equilibrium-moisture curves of different solids ____________________ ?
A. Are different
B. Depend on the humidity of the gas
C. Are same
D. None of these
In McCabe-Thiele method of theoretical plate calculation for a distillation column, the operating lines of stripping and rectifying sections coincide with the diagonal at ________________ reflux ?
A. Total
B. Operating
C. Minimum
D. Maximum permissible
Steady state equimolal counter diffusion occurs in case of ____________________?
A. Absorption
B. Leaching
C. Binary phase distillation
D. Liquid-liquid extraction
_____________ is used as an ‘entrainer’ for the separation of acetic acid-water mixture by distillation?
A. Benzol
B. Furfural
C. Butyl acetate
D. Hexane
If mass diffusivity in a mixture is equal to the thermal diffusivity, then the Lewis number is____________________
A. 0
B. 1
C. 4
D. 3
For continuous drying of granular or crystalline material, the dryer used is the _______________ dryer?
A. Tray
B. Tunnel
C. Rotary
D. None of these
In case of an absorber, the operating _______________?
A. Line always lies above the equilibrium curve
B. Line can be either above or below the equilibrium curve
C. Line always lies below the equilibrium curve
D. Velocity is more than the loading velocity
Radioactive nuclear waste is treated in____________________?
A. Rotating-disc contactor
B. Mixer-settler extractor
C. Pulsed column extractor
D. Bollman extractor
Langmuir equation is associated with________________________?
A. Steam distillation
B. Adsorption
C. Leaching
D. Multi-component absorption
Which of the following is an undesirable property for an absorbing solvent ?
A. Low velocity
B. Low vapour pressure
C. Low freezing point
D. None of these
Raoult’s law applies to the___________________?
A. Non-ideal solution only
B. All liquid solutions
C. Non-volatile solute
D. Solvents
A packed tower compared to a plate tower for a particular mass transfer operation__________________?
A. Incurs smaller pressure drop
B. Is less costly when built in large sizes/diameters
C. Allows installation of cooling coils
D. Is more suitable, if suspended solids are present in fluid streams
Stacked packing compared to dumped packing_________________?
A. Gives lower pressure drop
B. Provides poorer contact between the fluids
C. Both A. and B.
D. Gives higher pressure drop
_______________ developed the film theory ?
A. Higbie
B. Ergun
C. Fick
D. Levenspiel
Schmidt number is given by ___________________?
A. μ/ρDAB
B. Sh × Pe
C. Re × Pe
D. Re/Pe
Fenske equation determines the __________________?
A. Height of the distillation column
B. Maximum number of ideal plates
C. Minimum number of theoretical plates
D. Optimum reflux ratio
Hydrogenation of oil is carried out in a/an _______________ in Vanaspati manufacturing plant?
A. Agitated vessel
B. Bubble cap column
C. Sieve tray column
D. Packed tower
If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively ?
A. [xD/(RD + 1)], [(RD + 1)/RD]
B. [RD/(RD + 1)], [xD/(xD + 1)]
C. [xD/(RD + 1)], [RD/(RD + 1)]
D. None of these
Fuels And Combustion Mcqs
Which of the following equipments is not used for gas dispersion ?
A. Bubble cap tray towers
B. Agitated vessels
C. Perforated sieve tray towers
D. Spray towers
______________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids ?
A. Packed
B. Wetted wall
C. Plate
D. Spray
On addition of solute in the solvent, the ______________ of the solution decreases ?
A. Boiling point
B. Vapour pressure
C. Freezing point
D. Both B. and C.
When adsorption hysteresis is observed, the desorption equilibrium pressure is _________________ that obtained by adsorption?
A. Always lower than
B. Same as
C. Always higher than
D. Dependent on the system; can be either lower or higher than
Extraction of penicillin employs a ________________ extraction column?
A. Centrifugal
B. Plate
C. Packed
D. None of these
Which of these columns incurs the lowest pressure drop ?
A. Packed column (with stacked packing)
B. Bubble plate column
C. Packed column (with dumped packing)
D. Pulse column
‘Absorption with chemical reaction’ is involved in the removal of__________________?
A. Carbon dioxide from gaseous stream using alkaline solution
B. Ammonia from coke oven gas using refrigerated water
C. Benzol from coke oven gas using solar oil/wash oil
D. Tar from coke oven gas in primary gas coolers using chilled water
Which of the following mixtures does not form an azeotrope at atmospheric pressure ?
A. Methyl alcohol-acetone
B. Water-alcohol
C. Butyl acetate-water
D. None of these
McCabe-Thiele method of binary distillation does not assume that the__________________?
A. Sensible heat changes are negligible compared with latent heat changes
B. Heat of mixing is negligible
C. Molar latent heats of all components are equal
D. None of these
Which of the following same diameter columns gives lowest pressure drop per unit height ?
A. Sieve-plate column
B. Bubble-cap column
C. Packed column (stacked)
D. Randomly packed column
Absorption factor method is used to calculate the number of ideal stages, when_______________________?
A. Operating line lies below the equilibrium line
B. Operating line lies above the equilibrium line
C. Both operating and equilibrium lines are parallel
D. Pressure drop in the column is very high
Entrainer used in Azeotropic distillation should____________________?
A. Form a low boiling azeotrope with one of the constituents of the mixture
B. Have high latent heat of vaporisation
C. Form a new azeotrope of low relative volatility with one of the constituents of the mixture
D. Have high viscosity to provide high tray efficiency
A plait point is the point on the solubility curve, where the tie line reduces to a point. What is the number of plait point for a ternary system containing two pairs of partially miscible liquids ?
A. 0
B. 2
C. 1
D. 3
For the same process conditions, the reflux ratio of an unlagged distillation column___________________?
A. Increases in summer
B. Increases in winter
C. Decreases in winter
D. None of these
Minimum possible diameter of a packed column is decided mainly by the________________________?
A. Flooding
B. Liquid density
C. Gas viscosity
D. Liquid hold up
Ponchon-Savarit method analyses the fractional equipment based on___________________?
A. Material balance only
B. Enthalpy balance only
C. Both enthalpy and material balances
D. The assumption of constant molal-overflow
Dryer widely used in a textile industry is ______________ dryer?
A. Cylinder
B. Festoon
C. Conveyor
D. Tunnel
Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty ?
A. Bubble cap column
B. Sieve plate column
C. Randomly packed column
D. Wetted wall column
In a binary system, separation is very efficient, when the relative volatility is_______________?
A. < 1
B. > 1
C. 1
D. 0.5
The following plot gives the saturated humidity (He) versus temperature (T).Line joining (H1, T1) and (H2, T2) is the constant enthalpy line. Choose the correct one from among the alternatives A, B, C and D____________________?
A. T1-Dew point temp; T2-Wet bulb temp; T3-Dry bulb temp
B. T1-Dew point temp; T2-Dry bulb temp; T3-Wet bulb temp
C. T1-Wet bulb temp; T2-Dry bulb temp; T3-Dew point temp
D. T1-Dry bulb temp; T2-Wet bulb temp; T3-Dew point temp