For a distillation column operating at minimum reflux, the

concentration of liquid and vapour leaving a plate will be same.

number of plates required will be maximum.

is a static bed leaching equipment.

is used for extraction of oil from oilseed.

employs only counter-current extraction.

When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30¬∞C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system,$

as the acetone concentration increases, the solubility curves approach each other.

both the phases become identical at a particular common point on both the solubility curves called the plait point.

the distribution curve which is a plot between x (acetone concentration in one phase) and y (acetone concentration in other phase) is analogous to x-y curve used in distillation and absorption terminates on the x = y diagonal at the concentration of the plait point.

Which of the following is an undesirable property in a tower packing ?

Large weight of liquid retained.

With increase in pressure, the relative volatility for a binary system

either (a) or (b), depends on the system.

Pick out the wrong statement. Raoult's law does not apply, when the

chemical combination or molecular association between unlike molecules takes place in the formation of solution.

size of component molecules are not equal.

attractive forces between like and unlike molecules in the solution are approximately equal.

component molecules are nonpolar.

chemical combination or molecular association between unlike molecules takes place in the formation of solution.

Positive deviation from Raoult's law means a mixture whose total pressure is

less than that computed for ideality.

greater than that computed for ideality.

less than that computed for ideality.

less than the sum of the vapour pressure of the components.

In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of

condenser and reboiler surfaces.

area between operating line and 45¬∞ diagonal x-y diagram.

condenser and reboiler surfaces.

An example of elutioh is

separation of sugar from sugar beet by hot water.

separation of uranium oxide from its ore by H2SO4 in a Pachuca tank.

separation of sugar from sugar beet by hot water.

dissolution of tannin out of tree barks by water.

recovery of vegetable oils from seeds.

Which of these columns incurs the lowest pressure drop ?

Packed column (with dumped packing)

Packed column (with stacked packing)

Packed column (with dumped packing)

Overall efficiency of the distillation column is

the ratio of number of actual plates to ideal plates.

the ratio of number of ideal plates to actual plates.

the ratio of number of actual plates to ideal plates.

same as the Murphree efficiency.

always more than the point efficiency.

Mass transfer co-efficient of liquid is

affected much less by temperature than that for gases.

affected more by temperature than that for gases.

affected much less by temperature than that for gases.

not affected by the temperature.

The Hatta number is important in

gas absorption without chemical reaction.

gas absorption with chemical reaction.

In case of unsaturated air

dew point < wet bulb temperature

wet bulb temperature < dry bulb temperature

Freundlich equation applies to the adsorption of solute from

gaseous solutions at high pressure.

dilute solutions, over a small concentration range.

gaseous solutions at high pressure.

854 + Mcqs in Mass Transfer in Chemical Engineering Page 15 McqOptions

701.	For a distillation column operating at minimum reflux, the
A.	concentration of liquid and vapour leaving a plate will be same.
B.	reflux ratio will be maximum.
C.	number of plates required will be maximum.
D.	none of these.
Answer» D. none of these.

702.	Mass transfer co-efficient (K) and diffusivity (D) are related according to film theory as
A.	K ‚àù D
B.	K ‚àùD
C.	K ‚àù D1.5
D.	K ‚àù D2
Answer» B. K ‚àùD

703.	Bollman extractor
A.	is a static bed leaching equipment.
B.	is used for extraction of oil from oilseed.
C.	is a centrifugal extractor.
D.	employs only counter-current extraction.
Answer» C. is a centrifugal extractor.

704.	When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30¬∞C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system,$
A.	as the acetone concentration increases, the solubility curves approach each other.
B.	both the phases become identical at a particular common point on both the solubility curves called the plait point.
C.	the distribution curve which is a plot between x (acetone concentration in one phase) and y (acetone concentration in other phase) is analogous to x-y curve used in distillation and absorption terminates on the x = y diagonal at the concentration of the plait point.
D.	all (a), (b) and (c).
Answer» E.

705.	Moisture in a solid exerting an equilibrium vapour pressure equal to that of the pure liquid at the same temperature is called the __________ moisture.
A.	unbound
B.	critical
C.	free
D.	bound
Answer» B. critical

706.	Which of the following is an undesirable property in a tower packing ?
A.	Large surface per unit volume.
B.	Large free cross-section.
C.	Low weight per unit volume.
D.	Large weight of liquid retained.
Answer» E.

707.	Milk is dried usually in a __________ dryer.
A.	freeze
B.	spray
C.	tray
D.	rotary
Answer» C. tray

708.	With increase in pressure, the relative volatility for a binary system
A.	increases.
B.	decreases.
C.	remains same.
D.	either (a) or (b), depends on the system.
Answer» C. remains same.

709.	For continuous drying of grannular or crystalline material, the dryer used is the __________ dryer.
A.	tunnel
B.	tray
C.	rotary
D.	none of these
Answer» D. none of these

710.	At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent.
A.	100
B.	0
C.	50
D.	between 0 and 100
Answer» C. 50

711.	Which of the following remains constant during sensible cooling process ?
A.	Specific humidity
B.	Partial pressure of vapour
C.	Both (a) and (b)
D.	Neither (a) nor (b)
Answer» D. Neither (a) nor (b)

713.	Which of the following is not a continuous drier ?
A.	Drum drier
B.	Spray drier
C.	Tunnel drier
D.	Tray drier
Answer» E.

714.	Radioactive nuclear waste is treated in
A.	mixer-settler extractor
B.	rotating-disc contactor
C.	pulsed column extractor
D.	Bollman extractor
Answer» D. Bollman extractor

721.	A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height.
A.	42278
B.	30-40
C.	70-80
D.	90-100
Answer» B. 30-40

723.	To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate)
A.	increase both 'G' and 'S'.
B.	decrease both 'G' and 'S'.
C.	increase 'S' and decrease 'G'.
D.	increase 'G' and decrease 'S'
Answer» D. increase 'G' and decrease 'S'

712.	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

715.	Pick out the wrong statement. Raoult's law does not apply, when the
A.	size of component molecules are not equal.
B.	attractive forces between like and unlike molecules in the solution are approximately equal.
C.	component molecules are nonpolar.
D.	chemical combination or molecular association between unlike molecules takes place in the formation of solution.
Answer» D. chemical combination or molecular association between unlike molecules takes place in the formation of solution.

716.	__________ columns are used for liquid dispersion in a continuous gas phase.
A.	Packed
B.	Pulse
C.	Bubble cap
D.	Sieve plate
Answer» B. Pulse

717.	Positive deviation from Raoult's law means a mixture whose total pressure is
A.	greater than that computed for ideality.
B.	less than that computed for ideality.
C.	less than the sum of the vapour pressure of the components.
D.	none of these.
Answer» B. less than that computed for ideality.

718.	In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor.
A.	increases with increase in
B.	is one at unity value of
C.	both (a) and (b)
D.	neither (a) nor (b)
Answer» D. neither (a) nor (b)

719.	The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature.
A.	dew point
B.	wet bulb
C.	dry bulb
D.	none of these
Answer» E.

720.	In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
A.	area between operating line and 45¬∞ diagonal x-y diagram.
B.	condenser and reboiler surfaces.
C.	tower cross-section.
D.	none of these.
Answer» B. condenser and reboiler surfaces.

722.	An example of elutioh is
A.	separation of uranium oxide from its ore by H2SO4 in a Pachuca tank.
B.	separation of sugar from sugar beet by hot water.
C.	dissolution of tannin out of tree barks by water.
D.	recovery of vegetable oils from seeds.
Answer» B. separation of sugar from sugar beet by hot water.

724.	Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.
A.	less than
B.	more than
C.	same as
D.	very much less
Answer» C. same as

725.	At a given equilibrium pressure, with increase in temperature, the concentration of adsorbed gas on solid adsorbant
A.	increases
B.	decreases
C.	remains unchanged
D.	increases exponentially
Answer» C. remains unchanged

Explore topic-wise MCQs in Chemical Engineering.

For a distillation column operating at minimum reflux, the

Mass transfer co-efficient (K) and diffusivity (D) are related according to film theory as

Bollman extractor

When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30¬∞C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system,$

Moisture in a solid exerting an equilibrium vapour pressure equal to that of the pure liquid at the same temperature is called the __________ moisture.

Which of the following is an undesirable property in a tower packing ?

Milk is dried usually in a __________ dryer.

With increase in pressure, the relative volatility for a binary system

For continuous drying of grannular or crystalline material, the dryer used is the __________ dryer.

At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent.

Which of the following remains constant during sensible cooling process ?

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

Which of the following is not a continuous drier ?

Radioactive nuclear waste is treated in

Pick out the wrong statement. Raoult's law does not apply, when the

__________ columns are used for liquid dispersion in a continuous gas phase.

Positive deviation from Raoult's law means a mixture whose total pressure is

In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor.

The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature.

In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of

A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height.

An example of elutioh is

To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate)

Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.

At a given equilibrium pressure, with increase in temperature, the concentration of adsorbed gas on solid adsorbant

The relative saturation of an unsaturated mixture of gas and vapor is independent of the

Which of these columns incurs the lowest pressure drop ?

Which of the following plays an important role in problems of simultaneous heat and mass transfer ?

Rotary dryers cannot handle __________ materials.

According to Poiseuille's law, the permeability for gas flow through a capillary is proportional to (where, Œº = gas viscosity)

As complete saturation of an adsorbent is approached, the differential heat of adsrop-tion approaches

Overall efficiency of the distillation column is

Which of the following binary systems is an example of a maximum boiling azeotrope ?

Mass transfer co-efficient of liquid is

Mechanism of moisture removal in case of freeze drying of food stuff is by

Molality is defined as the number of gm moles of solute per __________ of solvent.

Mass transfer co-efficient is directly proportional to DAB0.5, according to __________ theory.

The Hatta number is important in

Polar organic compounds are normally used as separating agents for the azeotropic and extractive distillation. Which of the following is the most important factor to be considered for the choice of the separating agent for extractive distillation ?

If the overall efficiency and Murphree plate efficiency are equal, then both the equilibrium and operating lines are

The binary diffusivity in gases at atmospheric conditions is about

Penetration theory relates the average mass transfer co-efficient (K) with diffusivity (D) as

Which of the following is not a continuous leaching equipment ?

In case of unsaturated air

Separation of two or more components of a liquid solution can not be achieved by

Freundlich equation applies to the adsorption of solute from

Minimum possible diameter of a packed coloumn is decided mainly by the

The slope of the operating line for a single component co-current absorber when plotted in terms of mole ratio units is

Make up water is supplied during cooling tower operation to compensate for water losses due to

726.	The relative saturation of an unsaturated mixture of gas and vapor is independent of the
A.	nature of the vapor.
B.	temperature of the mixture.
C.	composition of the mixture.
D.	none of these.
Answer» E.

727.	Which of these columns incurs the lowest pressure drop ?
A.	Packed column (with stacked packing)
B.	Packed column (with dumped packing)
C.	Bubble plate column
D.	Pulse column
Answer» B. Packed column (with dumped packing)

728.	Which of the following plays an important role in problems of simultaneous heat and mass transfer ?
A.	Lewis number
B.	Schmidt number
C.	Prandtl number
D.	Sherwood number
Answer» B. Schmidt number

729.	Rotary dryers cannot handle __________ materials.
A.	free flowing
B.	dry
C.	sticky
D.	grannular
Answer» D. grannular

730.	According to Poiseuille's law, the permeability for gas flow through a capillary is proportional to (where, Œº = gas viscosity)
A.	Œº
B.	1/Œº
C.	Œº
D.	Œº2
Answer» C. Œº

731.	As complete saturation of an adsorbent is approached, the differential heat of adsrop-tion approaches
A.	that of normal condensation.
B.	integral heat of adsorption.
C.	zero.
D.	none of these.
Answer» B. integral heat of adsorption.

732.	Overall efficiency of the distillation column is
A.	the ratio of number of ideal plates to actual plates.
B.	the ratio of number of actual plates to ideal plates.
C.	same as the Murphree efficiency.
D.	always more than the point efficiency.
Answer» B. the ratio of number of actual plates to ideal plates.

733.	Which of the following binary systems is an example of a maximum boiling azeotrope ?
A.	Water-hydrochloric acid.
B.	Acetone-carbon disulphide.
C.	Water-ethyl alcohol.
D.	n-heptane-n-octane.
Answer» B. Acetone-carbon disulphide.

734.	Mass transfer co-efficient of liquid is
A.	affected more by temperature than that for gases.
B.	affected much less by temperature than that for gases.
C.	not affected by the temperature.
D.	none of these.
Answer» B. affected much less by temperature than that for gases.

735.	Mechanism of moisture removal in case of freeze drying of food stuff is by
A.	evaporation
B.	sublimation
C.	dehydration
D.	adsorption
Answer» C. dehydration