For absorbing a sparingly soluble gas in a liquid, the~!

Gas side co-efficient should be decreased

Gas side co-efficient should be increased

Liquid side coefficient should be increased

Gas side co-efficient should be decreased

Liquid side co-efficient should be decreased

For absorbing a sparingly soluble gas in a liquid, the

Gas side co-efficient should be decreased

Gas side co-efficient should be increased

Liquid side coefficient should be increased

Gas side co-efficient should be decreased

Liquid side co-efficient should be decreased

Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when%!

Only vapor phase follows Raoult's law

Only liquid phase obeys Dalton's law

Liquid phase obeys Dalton's law and vapor phase obeys Raoult's law

Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law

To get high tray efficiency%!

Time of contact between the two phases should be less

Interfacial surface between liquid and gas phase should be large

Time of contact between the two phases should be less

Gas velocity should be very low

Liquid entrainment should be severe

The binary diffusivity in gases at atmospheric conditions is about%!

10-4 cm¬¨‚â§/seC‚Äö√á√á

The wetted wall tower is used to determine%!

M.T.C. of individual components in a liquid-liquid system

Individual mass transfer co-efficient (M.T.C.) in gaseous system

M.T.C. of individual components in a liquid-liquid system

M.T.C. of liquid in liquid-gas system

The overall M.T.C. of the system

For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because%!

Water has a high latent heat of evaporation

They are always equal under all circumstances

Solubility of the components of air in water is very small

A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?%!

The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10

The mixture exhibits an azeotrope at 101.3 kPa

The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10

The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10

The mixture contain optical isomers

Pick out the wrong statement pertaining to the cooling towers.%!

In case of induced draft cooling tower, the fan is placed at the top of the tower

Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air

A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low

Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

For a ternery mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a __________ of the equilateral triangular co-ordinates.%!

Binary mixture is represented by the apex

Binary mixture is represented by any point inside

Ternery mixture is represented by the sides

Pure component is represented by the apex

Unsaturated air (with dry bulb temperature and dew point being 35¬¨‚àûC and 18¬¨‚àûC respectively) is passed through a water spray chamber maintained at 15¬¨‚àûC. The air will be cooled%!

And dehumidified with increase in wet bulb temperature

And dehumidified with decrease in wet bulb temperature

In saturated gas, the%!

Vapour is in equilibrium with the liquid at the room temperature

Vapour is in equilibrium with the liquid at the gas temperature

Vapour is in equilibrium with the liquid at the room temperature

Partial pressure of vapour equals the vapour pressure of the liquid at room temperature

Which of the following is not fixed by the process requirements, in the design of absorbers?%!

Composition of the entering liquid

Terminal concentrations of gas stream

In case of constant underflow extraction operation, the __________ at all solute concentration.%!

Solids are drained to the same extent

Ratio of the insoluble to solution is constant

The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is%!

Proportional to ‚Äö√ √∂D

Dependent on the Reynolds number

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)%!

Composition of the residue remains unchanged

Less number of trays are required

Composition of the residue remains unchanged

More number of trays are required but the residue composition remains unchanged

More number of trays are required and the residue composition is more dilute in methanol

With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency%!

May increase or decrease ; depends on individual design

When a multistage tray tower uses a minimum reflux ratio, it implies%!

Infinite trays and minimum reboiler heat load

Infinite trays and maximum reboiler heat load

Infinite trays and minimum reboiler heat load

Minimum trays and minimum reboiler heat load

Minimum trays and maximum reboiler heat load

Low viscosity absorbent is preferred for reasons of%!

Rapid absorption rates and good heat transfer characteristics

Improved flooding characteristics

In batch distillation with constant reflux, overhead product composition __________ with time.%!

May increase on decrease, depends on the system

Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature.%!

Either A or B; depends on the solid

Separation of __________ employs gaseous diffusion process.%!

N‚Äö√á√á and O‚Äö√á√á from air

Is a function of the mass transfer between liquid and vapour

Increases due to liquid entrainment

Increases due to weeping and dumping of liquid

591 + Mcqs in Mass Transfer in Chemical Engineering Page 1 McqOptions

1.	For absorbing a sparingly soluble gas in a liquid, the~!
A.	Gas side co-efficient should be increased
B.	Liquid side coefficient should be increased
C.	Gas side co-efficient should be decreased
D.	Liquid side co-efficient should be decreased
Answer» C. Gas side co-efficient should be decreased

Discussion

2.	For absorbing a sparingly soluble gas in a liquid, the
A.	Gas side co-efficient should be increased
B.	Liquid side coefficient should be increased
C.	Gas side co-efficient should be decreased
D.	Liquid side co-efficient should be decreased
Answer» C. Gas side co-efficient should be decreased

Discussion

3.	Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when%!
A.	Only vapor phase follows Raoult's law
B.	Only liquid phase obeys Dalton's law
C.	Liquid phase obeys Dalton's law and vapor phase obeys Raoult's law
D.	Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law
Answer» E.

Discussion

4.	To get high tray efficiency%!
A.	Interfacial surface between liquid and gas phase should be large
B.	Time of contact between the two phases should be less
C.	Gas velocity should be very low
D.	Liquid entrainment should be severe
Answer» B. Time of contact between the two phases should be less

Discussion

5.	The binary diffusivity in gases at atmospheric conditions is about%!
A.	10-9 cm/sec
B.	10-1 cm¬¨‚â§/sec
C.	10-3 sec/cm
D.	10-4 cm¬¨‚â§/seC‚Äö√á√á
Answer» C. 10-3 sec/cm

Discussion

6.	A good solvent used for absorption should not have very high%!
A.	Viscosity
B.	Vapor pressure
C.	Freezing point
D.	All of the above
Answer» E.

Discussion

7.	__________ extractor uses centrifugal force for separating the two phases.%!
A.	Treybal
B.	Schiebel
C.	Podbielniak
D.	None of these
Answer» D. None of these

Discussion

8.	Small dia distillation column can be a%!
A.	Packed column
B.	Sieve tray
C.	Bubble cap
D.	Any of these
Answer» B. Sieve tray

Discussion

9.	Unsaturated air (with dry and wet bulb temperatures being 35 and 25¬¨‚àûC respectively) is passed through water spray chamber maintained at 35¬¨‚àûC. The air will be%!
A.	Cooled
B.	Humidified
C.	Both A & B
D.	Dehumidified
Answer» C. Both A & B

Discussion

10.	Humid volume, at a given temperature is a/an __________ function of humidity.
A.	Inverse
B.	Exponential
C.	Linear
D.	Logarithmic
Answer» D. Logarithmic

Discussion

11.	For the case of flow of air past a wet bulb thermometer (air water vapour system), the approximate value of H‚Äö√á√á/ky.Cz is around%!
A.	0.60
B.	0.24
C.	1
D.	0.72
Answer» D. 0.72

Discussion

12.	The wetted wall tower is used to determine%!
A.	Individual mass transfer co-efficient (M.T.C.) in gaseous system
B.	M.T.C. of individual components in a liquid-liquid system
C.	M.T.C. of liquid in liquid-gas system
D.	The overall M.T.C. of the system
Answer» B. M.T.C. of individual components in a liquid-liquid system

Discussion

13.	For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because%!
A.	Water has a high latent heat of evaporation
B.	Lewis number is close to unity
C.	They are always equal under all circumstances
D.	Solubility of the components of air in water is very small
Answer» B. Lewis number is close to unity

Discussion

14.	A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?%!
A.	The mixture exhibits an azeotrope at 101.3 kPa
B.	The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10
C.	The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10
D.	The mixture contain optical isomers
Answer» B. The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10

Discussion

15.	The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture.%!
A.	Composition
B.	Temperature
C.	Total pressure
D.	All of the above
Answer» C. Total pressure

Discussion

16.	Detergent solution is dried to a powder in a%!
A.	Spray dryer
B.	Spouted bed dryer
C.	Tunnel dryer
D.	Pan open to atmosphere
Answer» B. Spouted bed dryer

Discussion

17.	Pick out the wrong statement pertaining to the cooling towers.%!
A.	In case of induced draft cooling tower, the fan is placed at the top of the tower
B.	Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air
C.	A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low
D.	Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature
Answer» E.

Discussion

18.	For a ternery mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a __________ of the equilateral triangular co-ordinates.%!
A.	Binary mixture is represented by the apex
B.	Binary mixture is represented by any point inside
C.	Ternery mixture is represented by the sides
D.	Pure component is represented by the apex
Answer» E.

Discussion

19.	Smoke is an example of%!
A.	Solid dispersed in liquid
B.	Solid dispersed in gas
C.	Liquid dispersed in gas
D.	Gas dispersed in liquid
Answer» C. Liquid dispersed in gas

Discussion

20.	At what value of reflux ratio, number of theoretical plates in a distillation column is minimum?%!
A.	0
B.	1
C.	‚Äö√ √ª
D.	< 1
Answer» D. < 1

Discussion

21.	Unsaturated air (with dry bulb temperature and dew point being 35¬¨‚àûC and 18¬¨‚àûC respectively) is passed through a water spray chamber maintained at 15¬¨‚àûC. The air will be cooled%!
A.	And humidified
B.	And dehumidified with increase in wet bulb temperature
C.	At the same relative humidity
D.	And dehumidified with decrease in wet bulb temperature
Answer» E.

Discussion

22.	__________ column is used in gas absorption process.%!
A.	Wetted wall
B.	Seive/perforated tray
C.	Bubble cap
D.	Packed
Answer» E.

Discussion

23.	Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number.%!
A.	Sherwood
B.	Schmidt
C.	Peclet
D.	Stanton
Answer» B. Schmidt

Discussion

24.	Separation of the isotopes of helium for scientific investigations is done by%!
A.	Reverse osmosis
B.	Thermal diffusion
C.	Leaching
D.	Solvent extraction
Answer» C. Leaching

Discussion

25.	With increase in solvent rate, the number of transfer units, NtoG, for a fixed degree of absorption from a fixed amount of gas%!
A.	Increases
B.	Decreases
C.	Decreases linearly
D.	Remains unaffected
Answer» C. Decreases linearly

Discussion

26.	At __________ reflux, theoretical number of plates in a distillation coloumn is calculated using Fenske-Underwood equation.%!
A.	Operating
B.	Total
C.	Minimum
D.	Maximum permissible
Answer» C. Minimum

Discussion

27.	In saturated gas, the%!
A.	Vapour is in equilibrium with the liquid at the gas temperature
B.	Vapour is in equilibrium with the liquid at the room temperature
C.	Partial pressure of vapour equals the vapour pressure of the liquid at room temperature
D.	None of these
Answer» B. Vapour is in equilibrium with the liquid at the room temperature

Discussion

28.	Nitrobenzene (boiling point = 210.6¬¨‚àûC) is steam distilled at 1 atm pressure.Nitrobenzene will distill off __________ ¬¨‚àûC.%!
A.	At < 100
B.	At > 210.6
C.	Between 100 and 210
D.	None of these
Answer» B. At > 210.6

Discussion

29.	Dry bulb temperature of the gas is __________ the wet bulb temperature.%!
A.	Less than
B.	More than
C.	Equal to
D.	None of these
Answer» C. Equal to

Discussion

30.	An air-water vapour mixture has a dry bulb temperature of 60¬¨‚àûC and a dew point temperature of 40¬¨‚àûC. The total pressure is 101.3 kPa and the vapour pressure of water at 40¬¨‚àûC and 60¬¨‚àûC are 7.30 kPa and 19.91 kPa respectively.The humidity of air sample expressed as kg of water vapour/kg of dry air is%!
A.	0.048
B.	0.079
C.	0.122
D.	0.152
Answer» E.

Discussion

31.	Which of the following is not fixed by the process requirements, in the design of absorbers?%!
A.	Flow rate of the entering gas
B.	Composition of the entering liquid
C.	Terminal concentrations of gas stream
D.	None of these
Answer» E.

Discussion

32.	In case of constant underflow extraction operation, the __________ at all solute concentration.%!
A.	Solids are drained to the same extent
B.	Ratio of the insoluble to solution is constant
C.	Both A & B
D.	Neither A nor B
Answer» D. Neither A nor B

Discussion

33.	The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is%!
A.	D/a
B.	D/2a
C.	Proportional to ‚Äö√ √∂D
D.	Dependent on the Reynolds number
Answer» E.

Discussion

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

Discussion

35.	Weight of 1 m¬¨‚â• of humid air as compared to 1 m¬¨‚â• of dry air, under the same conditions, is%!
A.	Less
B.	More
C.	Same
D.	Unpredictable
Answer» B. More

Discussion

36.	The dew point of a saturated gas phase equals the __________ temperature.%!
A.	Gas
B.	Room
C.	Wet bulb
D.	None of these
Answer» B. Room

Discussion

37.	Desulphurisation of petrol is done in a%!
A.	Bollman extractor
B.	Rotating disc extractor
C.	Packed extraction column
D.	Plate type extraction column
Answer» C. Packed extraction column

Discussion

38.	__________ is concerned with the adsorption equilibria.%!
A.	Fick's law
B.	Gibb's equation
C.	Freundlich equation
D.	None of these
Answer» D. None of these

Discussion

39.	Dorr thickener is an equipment used for%!
A.	Classification
B.	Sedimentation
C.	Clarification
D.	Leaching
Answer» C. Clarification

Discussion

40.	Lewis number (Le) is%!
A.	Sc x Pr
B.	Pr x St
C.	Sh x Pr
D.	St x Sh
Answer» B. Pr x St

Discussion

41.	With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency%!
A.	Increases
B.	Decreases
C.	Remains same
D.	May increase or decrease ; depends on individual design
Answer» B. Decreases

Discussion

42.	Deairation (removal of O‚Äö√á√á) of water is done by%!
A.	Rectification
B.	Absorption
C.	Ion-exchange
D.	Adsorption
Answer» D. Adsorption

Discussion

43.	When a multistage tray tower uses a minimum reflux ratio, it implies%!
A.	Infinite trays and maximum reboiler heat load
B.	Infinite trays and minimum reboiler heat load
C.	Minimum trays and minimum reboiler heat load
D.	Minimum trays and maximum reboiler heat load
Answer» B. Infinite trays and minimum reboiler heat load

Discussion

44.	Low viscosity absorbent is preferred for reasons of%!
A.	Rapid absorption rates and good heat transfer characteristics
B.	Improved flooding characteristics
C.	Low pressure drop on pumping
D.	All of the above
Answer» E.

Discussion

45.	In batch distillation with constant reflux, overhead product composition __________ with time.%!
A.	Increases
B.	Decreases
C.	Does not vary
D.	May increase on decrease, depends on the system
Answer» C. Does not vary

Discussion

46.	Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature.%!
A.	Less than
B.	More than
C.	Equal to
D.	Either A or B; depends on the solid
Answer» B. More than

Discussion

47.	With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________ , if the conduction and radiation through the solid are negligible.%!
A.	Increases
B.	Decreases
C.	Remains same
D.	Increases linearly
Answer» B. Decreases

Discussion

48.	Separation of __________ employs gaseous diffusion process.%!
A.	N‚Äö√á√á and O‚Äö√á√á from air
B.	Isotopes of uranium
C.	Isotopes of helium
D.	SO‚Äö√á√á and air
Answer» C. Isotopes of helium

Discussion

49.	Plate efficiency%!
A.	Is a function of the mass transfer between liquid and vapour
B.	Increases due to foaming
C.	Increases due to liquid entrainment
D.	Increases due to weeping and dumping of liquid
Answer» B. Increases due to foaming

Discussion

50.	A minimum boiling azeotrope is exemplified by%!
A.	Toluene-benzene
B.	Acetone-carbon disulphide
C.	Water-isobutyl alcohol
D.	None of these
Answer» C. Water-isobutyl alcohol

Discussion

Explore topic-wise MCQs in Chemical Engineering.

For absorbing a sparingly soluble gas in a liquid, the~!

For absorbing a sparingly soluble gas in a liquid, the

Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when%!

To get high tray efficiency%!

The binary diffusivity in gases at atmospheric conditions is about%!

A good solvent used for absorption should not have very high%!

__________ extractor uses centrifugal force for separating the two phases.%!

Small dia distillation column can be a%!

Unsaturated air (with dry and wet bulb temperatures being 35 and 25¬¨‚àûC respectively) is passed through water spray chamber maintained at 35¬¨‚àûC. The air will be%!

Humid volume, at a given temperature is a/an __________ function of humidity.

For the case of flow of air past a wet bulb thermometer (air water vapour system), the approximate value of H‚Äö√á√á/ky.Cz is around%!

The wetted wall tower is used to determine%!

For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because%!

A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?%!

The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture.%!

Detergent solution is dried to a powder in a%!

Pick out the wrong statement pertaining to the cooling towers.%!

For a ternery mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a __________ of the equilateral triangular co-ordinates.%!

Smoke is an example of%!

At what value of reflux ratio, number of theoretical plates in a distillation column is minimum?%!

Unsaturated air (with dry bulb temperature and dew point being 35¬¨‚àûC and 18¬¨‚àûC respectively) is passed through a water spray chamber maintained at 15¬¨‚àûC. The air will be cooled%!

__________ column is used in gas absorption process.%!

Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number.%!

Separation of the isotopes of helium for scientific investigations is done by%!

With increase in solvent rate, the number of transfer units, NtoG, for a fixed degree of absorption from a fixed amount of gas%!

At __________ reflux, theoretical number of plates in a distillation coloumn is calculated using Fenske-Underwood equation.%!

In saturated gas, the%!

Nitrobenzene (boiling point = 210.6¬¨‚àûC) is steam distilled at 1 atm pressure.Nitrobenzene will distill off __________ ¬¨‚àûC.%!

Dry bulb temperature of the gas is __________ the wet bulb temperature.%!

Which of the following is not fixed by the process requirements, in the design of absorbers?%!

In case of constant underflow extraction operation, the __________ at all solute concentration.%!

The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is%!

Weight of 1 m¬¨‚â• of humid air as compared to 1 m¬¨‚â• of dry air, under the same conditions, is%!

The dew point of a saturated gas phase equals the __________ temperature.%!

Desulphurisation of petrol is done in a%!

__________ is concerned with the adsorption equilibria.%!

Dorr thickener is an equipment used for%!

Lewis number (Le) is%!

With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency%!

Deairation (removal of O‚Äö√á√á) of water is done by%!

When a multistage tray tower uses a minimum reflux ratio, it implies%!

Low viscosity absorbent is preferred for reasons of%!

In batch distillation with constant reflux, overhead product composition __________ with time.%!

Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature.%!

With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________ , if the conduction and radiation through the solid are negligible.%!

Separation of __________ employs gaseous diffusion process.%!

Plate efficiency%!

A minimum boiling azeotrope is exemplified by%!