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New Mass Transfer MCQs – Most Competitive Chemical Engineering MCQs

New Mass Transfer MCQs – Most Competitive Chemical Engineering MCQs

This post is comprising of latest ” Mass Transfer MCQs – Latest Competitive Chemical Engineering MCQs “. Here you’ll get latest chemical engineering mcqs for written test, interview with answers. If you want to improve your knowledge regarding chemical engineering then read these mcqs of Design of Steel Structures.

Latest Chemical Engineering MCQs

By practicing these MCQs of Mass Transfer MCQs – Latest Competitive Chemical Engineering MCQs , an individual for exams performs better than before. This post comprising of mechanical engineering objective questions and answers related to Mass Transfer Mcqs “. As wise people believe “Perfect Practice make a Man Perfect”. It is therefore practice these mcqs of Chemical engineering to approach the success. Tab this page to check “Mass Transfer Mcqs” for the preparation of competitive mcqs, FPSC mcqs, PPSC mcqs, SPSC mcqs, KPPSC mcqs, AJKPSC mcqs, BPSC mcqs, NTS mcqs, PTS mcqs, OTS mcqs, Atomic Energy mcqs, Pak Army mcqs, Pak Navy mcqs, CTS mcqs, ETEA mcqs and others.

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:

_________________ is the separation technique used for desalination of sea water ?

A. Adsorption
B. Reverse osmosis
C. Thermal diffusion
D. Absorption

A distillation column separates 10000 kg/hr of a benzene-toluene mixture as shown in the figure below: In the figure xF, xD and xW represent the weight fraction of benzene in the feed, distillate and residue respectively. The reflux ratio is_______________ ?

A. 1.0
B. 0.6
C. 0.5
D. 2.0

Out of two equilibrium curves, first one lies above the diagonal and the second lies below the diagonal in the x-y plot. It means that separation by distillation is_________________?

A. Not possible in the second case unless high pressure is applied
B. Not possible in the second case unless vacuum is applied
C. More readily done in the second case compared to first one
D. None of these

The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an _________________ law?

A. Exponential
B. Linear
C. Parabolic
D. Cubic

Wet bulb and dry bulb temperatures becomes identical at _______________ percent saturation curve?

A. 100
B. 78
C. 50
D. None of these

According to Chilton-Colburn analogy for mass transfer, NSt.NSc 2/3 is equal to_________________?

A. 2f
B. f/2
C. f
D. 1/f

If „f’ is defined as above, then which of the following applies to a feed at dew point ?

A. f = 1
B. f 1
C. 0 < f < 1
D. 0 > f > 1

Flash distillation is suitable for the separation of components_________________?

A. Which form maximum boiling azeotrope
B. Having very close boiling points
C. Having very wide boiling points
D. Which form minimum boiling azeotrope

Separation of the isotopes of helium for scientific investigations is done by_____________________?

A. Leaching
B. Thermal diffusion
C. Reverse osmosis
D. Solvent extraction

Very tall packed towers are divided into series of beds to___________________?

A. Reduce liquid hold-up
B. Avoid channeling
C. Reduce the overall pressure drop
D. Avoid flooding

The McCabe ΔL law states that the____________________?

A. Linear crystal growth rate depends on the degree of super-saturation
B. Molar heats of vaporisation of components are nearly equal
C. Linear crystal growth rate does not depend on the crystal size
D. Linear crystal growth rate depends on the crystal size

When both the fluids flow concurrently in an absorber, the slope of the operating line is____________________?

A. -ve
B. 1
C. +ve
D. -1

Steam distillation is used for separation of high boiling ____________________?

A. Volatile impurity from still higher boiling substances
B. Substances from non-volatile impurities
C. Both A. and B.
D. Neither A. nor B.

The relative saturation of a partially saturated mixture of vapour and gas can be increased by ________________ of the mixture?

A. Reducing the total pressure
B. Reducing the temperature
C. Increasing the total pressure
D. Both B. and C.

For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams__________________?

A. Increases
B. Remain unaffected
C. Decreases
D. Passes through a maximum

_______________ diffusion is used for separating the isotopes of methane ?

A. Thermal
B. Concentration
C. Pressure
D. Force

For a distillation column operating at minimum reflux, the_______________________?

A. Reflux ratio will be maximum
B. Concentration of liquid and vapour leaving a plate will be same
C. Number of plates required will be maximum
D. None of these

According to the film theory of mass transfer, the mass transfer co-efficient is proportional to (where, D = molecular diffusivity) ?

A. D
B. D0.5
C. D2
D. 1/D

Compound A is extracted from a solution of A + B into a pure solvent S. A Co-current unit is used for the liquid-liquid extraction. The inlet rate of the solution containing A is 200 moles of B/hr.m2 and the solvent flow, rate is 400 moles of S/m2. hr. The equilibrium data is represented by Y = 3X2 , where Y is in moles of a A/moles of B and X is in moles A/moles of S. The maximum percentage extraction achieved in the unit is_________________________?

A. 70%
B. 50%
C. 25%
D. 90%

Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty ?

A. Grid tray tower
B. Wetted wall tower
C. Perforated tray tower
D. Bubble cap tower

Mass transfer co-efficient is directly proportional to DAB 0.5, according to ________________ theory ?

A. Penetration
B. Film
C. Surface renewal
D. None of these

Fuels And COmbustion Mcqs

For experimental determination of mass transfer co-efficient by wetted wall tower, the mass transfer area is___________________?

A. Unknown
B. Calculated
C. Known
D. Not required

With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency____________________?

A. Increases
B. Remain same
C. Decreases
D. May increase or decrease; depends on individual design

Diameter to height ratio for a raschig ring is_____________________?

A. 1
B. 8
C. 2
D. 0.5

Which of the following operations does not involve leaching ?

A. Dissolving sugar from the cells of the beet
B. Dissolving pharmaceutical products from bark or roots
C. Dissolving gold from ores
D. Removing nicotine from its water solution by kerosene

Flooding in a distillation column is detected by a sharp ___________________?

A. Increase in Murphree plate efficiency
B. Decrease in liquid hold up in the column
C. Decrease in pressure drop
D. Increase in pressure drop

In case of an ideal solution, the total vapor pressure varies ______________ with the composition expressed as mole fraction?

A. Exponentially
B. Linearly
C. Inversely
D. None of these

With increase in temperature, the rate of extraction in leaching (solid-liquid extraction system) ?

A. Increases
B. Decreases
C. Increases Linearly
D. Remain unaffected

Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion, if____________________?

A. Mass transfer is accompanied by reaction
B. Molecular mean free path is high
C. Diffusion of A is in stagnant medium B
D. There is equimolar counter diffusion

Absorption accompanied by heat evolution results in____________________?

A. Increase in equilibrium solubility
B. Increased capacity of the absorber
C. Decrease in equilibrium solubility
D. None of these

The solvent used in liquid extraction should not have high latent heat of vaporisation, because ______________________?

A. The pressure drop and hence the pumping cost will be very high
B. It will decompose while recovering by distillation
C. Its recovery cost by distillation may be prohibitively high
D. It cannot be recovered by distillation

Mass transfer co-efficient varies as DAB 0.5, according to the _______________ theory?

A. Penetration
B. Surface renewal
C. Film
D. None of these

The suitable evaporator for concentration of foaming liquids is a ______________________ evaporator?

A. Long tube
B. Vacuum
C. Short tube
D. Falling film

In stripping section of continuous distillation column, the_______________________?

A. Vapour is stripped of low boiler
B. Liquid is enriched with high boiler
C. Liquid is stripped of high boiler
D. None of these

An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii) ____________________?

A. Less number of trays are required
B. More number of trays are required but the residue composition remains unchanged
C. Composition of the residue remains unchanged
D. More number of trays are required and the residue composition is more dilute in methanol

Mechanical Operations Mcqs

The Schmidt number which is defined as, μ/ρ D, is the ratio of the_____________________?

A. Momentum diffusivity to the mass diffusivity
B. Momentum diffusivity to the thermal diffusivity
C. Thermal diffusivity to the mass diffusivity
D. None of these

NSc/NPr is called the______________________?

A. Sherwood number
B. Lewis number
C. Psychrometric ratio
D. Stanton number

At constant pressure, with increase of temperature, the dew point will ________________________?

A. Increase
B. Remain unchanged
C. Decrease
D. Increase/decrease; depends on the temperature

The percentage humidity is less than the relative humidity only at __________________ percent humidity?

A. Hundred
B. Zero
C. Both zero and hundred
D. None of these

‘ADDUCTS’ and ‘CLATHRATES’ are used in case of_____________________?

A. Absorption
B. Crystallisation
C. Extractive distillation
D. None of these

__________________ is concerned with the adsorption equilibria?

A. Gibb’s equation
B. Fick’s law
C. Freundlich equation
D. None of these

In most of the vacuum crystalliser, vacuum is generally produced by means of a_____________________?

A. Compressed air jet
B. Suction pump
C. Steam jet ejector with a barometric condenser
D. None of these

The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will______________________?

A. Increase
B. Remain same
C. Decrease
D. Depend on saturated boiling point; may increase or decrease

In a distillation column, with increase in the reflux ratio, the heat removed in the cooler ______________________?

A. Increases
B. Remains unaffected
C. Decreases
D. And the heat required in reboiler decreases

During constant rate drying period, vaporisation rate per unit drying surface area _____________________?

A. Increases with time
B. Decreases with time
C. Does not change with time
D. Does not affect the moisture content of the wet solid

A coalescer in a mixer-settler liquid-liquid extraction column______________________?

A. Comprises of thin bed of substances of extended surface having high porosity
B. Helps in increasing the settling rate of the bubbles
C. Helps in increasing the bubble size entering the settler
D. All ‘a’, ‘b’, & ‘c’

In which of the following unit operations, the selectivity is an important parameter ?

A. Absorption
B. Solvent extraction
C. Distillation
D. None of these

Flash distillation is suitable for separating the constituents of a binary system, which _____________________?

A. Have very close boiling points
B. Have very wide boiling points
C. Form minimum boiling azeotrope
D. Form constant boiling azeotrope

In case of an unsaturated mixture of gas and vapor, the percentage saturation is __________________ its relative saturation?

A. Lower than
B. Equal to
C. Higher than
D. Either A. or B., depends on the mixture composition

At __________________ reflux, theoretical number of plates in a distillation coloumn is calculated using Fenske-Underwood equation?

A. Minimum
B. Total
C. Operating
D. Maximum permissible

In physical terms, Schmidt number means _________________?

A. Thermal diffusivity/momentum diffusivity
B. Thermal diffusivity/mass diffusivity
C. Momentum diffusivity/mass diffusivity
D. Mass diffusivity/thermal diffusivity

Chemical Process Mcqs

Unit operation involved in the prilling of urea is_____________________?

A. Evaporation
B. Crystallisation
C. Drying
D. Both B. and C.

Degree of freedom for leaching and solvent extraction process is_____________________?

A. 1
B. 0
C. 2
D. 3

With increase in temperature, the solubility of gases in liquids, at fixed pressure____________________?

A. Remain same
B. Decreases
C. Increases
D. Either A. or B., depends on the system

The equipment used in the extraction of highly corrosive radioactive liquids is_______________________?

A. Pulse column
B. Mixer settler
C. Spray column
D. Baffle tower

Tea percolation employs___________________________?

A. Absorption
B. Leaching
C. Liquid-liquid extraction
D. None of these

When the solvent dissolves very little of solute, then__________________________?

A. Solvent of low freezing point should be used
B. Solvent of low latent heat of vaporisation should be used
C. Large quantity of solvent is required to extract the solute
D. Very small quantity of solvent is required

Bollman extractor___________________?

A. Is a centrifugal extractor
B. Is used for extraction of oil from oilseed
C. Is a static bed leaching equipment
D. Employs only counter-current extraction

In case of absorption, both the operating and equilibrium lines will be straight for______________?

A. Dilute solutions
B. Isothermal operation
C. Dilute solutions and isothermal operation
D. None of these

The most economical range of absorption factor is____________________?

A. 0 to 3
B. 0 to 0.5
C. 1.25 to 2
D. 5 to 15

In the constant rate period of the rate of drying curve for batch drying,_________________?

A. Rate of drying decreases abruptly
B. Cracks develop on the surface of the solid
C. Surface evaporation of unbound moisture occurs
D. None of these

Back-trapping in a distillation column ?

A. Reduces pressure drop
B. Decreases tray efficiency
C. Increases tray efficiency
D. Is desirable, as it provides improved vapour-liquid contact

Rose oil is extracted from rose leaves using ____________ distillation?

A. Low pressure
B. High pressure
C. Extractive
D. Steam

The value of NA/(NA + NB), for steady state equimolal counter diffusion of two gases ‘A’ and ‘B’ is____________?

A. 0.5
B. ∞
C. 1
D. 2

Which of the following is not a unit of mass transfer co-efficient ?

A. Moles transferred/ [(time) (area) (pressure)]
B. Moles transferred/ [(time) (area) (mass A/mass B)]
C. Moles transferred/ [(time) (area) (mole fraction)]
D. None of these

Dry bulb temperature of the gas is _____________ the wet bulb temperature?

A. Equal to
B. More than
C. Less than
D. None of these

The equilibrium liquid composition compared to the vapor composition in case of Azeotropic mixture is________________?


A. Less
B. More
C. Same
D. Either more or less; depends on the system

Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled_________________?

A. At the same relative humidity
B. And dehumidified with increase in wet bulb temperature
C. And humidified
D. And dehumidified with decrease in wet bulb temperature

The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around_________________?

A. 1
B. 0.24
C. 600
D. 3.97

Dew point of an air-water vapor mixture_________________?

A. At constant humidity & total pressure is fixed
B. Decreases with decrease in pressure
C. Corresponding to any point on the humidity chart is obtained by projecting a line through this point parallel to the temperature axis and to the saturation curve
D. All A , B. & C.

New Mass Transfer MCQs – Most Competitive Chemical Engineering MCQs