Powdery materials can be guarded against caking tendency on storage by_________________?

Providing minimum percentage of voids

Having maximum possible points of contact

Powdery materials can be guarded against caking tendency on storage by___________________?

Providing minimum percentage of voids

Having maximum possible points of contact

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

Ponchon-Savarit method analyses the fractional equipment based on___________________?

The assumption of constant molal-overflow

Both enthalpy and material balances

The assumption of constant molal-overflow

Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the____________________?

Pressure drop in the equipment will be very high

Packing may be crushed due to thermal expansion/contraction of the components of the equipments

Pressure drop in the equipment will be very high

Viscosity variation of the fluids may cause channelling/flooding

Plate efficiency_______________________?

Is a function of the mass transfer between liquid and vapour

Increases due to liquid entrainment

Increases due to weeping and dumping of liquid

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 non-polar

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

Pick out the wrong statement pertaining to the rotary dryer ?

Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute

Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it down through the current of hot air/gases. It extend

Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at any instant. The best performance for rotary drier i

Rotary dryer is suitable for drying sticky material

Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute

Pick out the wrong statement pertaining to leaching ?

Door classifier can be used for leaching of coarse solids

Fine solids cannot be leached in a Pachuca tank

Door classifier can be used for leaching of coarse solids

Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor

Very high temperature is not needed for the leaching of sugar beet

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

Pick out the wrong statement pertaining to the analogy between equations of heat and mass_________________?

Reynolds number remains the same in both heat and mass transfer

Sherwood number in mass transfer is analogous to Nusselt number in heat transfer

Prandtl number in heat transfer is analogous to Schmidt number in mass transfer

Reynolds number in mass transfer is analogous to Grashoff number in heat transfer

Reynolds number remains the same in both heat and mass transfer

Pick out the wrong statement. Generally for physical adsorption, a gas of________________?

Higher molecular weight is adsorbed in preference to a gas of low molecular weight

High critical temperature is adsorbed in preference to a gas of low critical temperature

Low volatility is adsorbed in preference to a gas of high volatility

Physical absorption is__________________?

Accompanied by evolution of heat

pertaining to the analogy between equations of heat and mass transfer operations ?_x005F_x000D_Pick out the wrong statement

Reynolds number remains the same in both heat and mass transfer

Sherwood number in mass transfer is analogous to Nusselt number in heat transfer

Prandtl number in heat transfer is analogous to Schmidt number in mass transfer

Reynolds number in mass transfer is analogous to Grashoff number in heat transfer

Reynolds number remains the same in both heat and mass transfer

Perforated plate towers are unique for solvent extraction because, they provide_____________________?

Repeated coalescence & redispersion of the drop phase

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

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_________________?

Not possible in the second case unless vacuum is applied

Not possible in the second case unless high pressure is applied

More readily done in the second case compared to first one

One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect ?

Neither the product composition nor the fraction vaporised

The product composition but not the fraction vaporised

The product composition as well as the fraction vaporised

The fraction vaporised but not the product composition

Neither the product composition nor the fraction vaporised

On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in______________________?

Greater degree of separation with a fixed number of trays

Molecular sieves are porous____________________?

Synthetic zeolites crystals/metal alumino-silicates

Molecular diffusivity of a liquid__________________?

May increase or decrease with temperature

Molecular diffusion is caused by the________________?

Activation energy of the molecules

Transfer of molecules from low concentration to high concentration region

Thermal energy of the molecules

Activation energy of the molecules

Potential energy of the molecules

590 + Mcqs in Mass Transfer for Chemical in Chemical Engineering Page 5 McqOptions

201.	Prandtl number for water at 20°C is about ________________?
A.	7
B.	70
C.	0.7
D.	150
Answer» B. 70

202.	Powdery materials can be guarded against caking tendency on storage by_________________?
A.	Providing irregular grain size
B.	Providing minimum percentage of voids
C.	Having maximum possible points of contact
D.	None of these
Answer» E.

203.	Powdery materials can be guarded against caking tendency on storage by___________________?
A.	Providing irregular grain size
B.	Providing minimum percentage of voids
C.	Having maximum possible points of contact
D.	None of these
Answer» E.

204.	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

205.	Pore size of the molecular sieve 5A is ____________________ mm ?
A.	5
B.	0.5
C.	0.05
D.	50
Answer» C. 0.05

206.	Ponchon-Savarit method analyses the fractional equipment based on___________________?
A.	Enthalpy balance only
B.	Material balance only
C.	Both enthalpy and material balances
D.	The assumption of constant molal-overflow
Answer» D. The assumption of constant molal-overflow

207.	Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the____________________?
A.	Packing may be crushed due to thermal expansion/contraction of the components of the equipments
B.	Pressure drop in the equipment will be very high
C.	Viscosity variation of the fluids may cause channelling/flooding
D.	None of these
Answer» B. Pressure drop in the equipment will be very high

208.	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

209.	Plate efficiency in a distillation column is reduced due to the ______________________ of liquid?
A.	Entrainment
B.	Foaming
C.	Weeping & dumping
D.	All A., B. & C.
Answer» E.

210.	Plate efficiency in a distillation column is reduced due to the ______________ of liquid?
A.	Entrainment
B.	Foaming
C.	Weeping & dumping
D.	All A., B. & C.
Answer» E.

211.	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 non-polar
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

217.	Pick out the system with minimum boiling azeotrope at 1 atm ?
A.	Benzene-toluene
B.	Ethyl alcohol-water
C.	Hydrochloric acid-water
D.	All A., B. and C.
Answer» C. Hydrochloric acid-water

218.	Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.) ?
A.	(1 + Ro) = Ro/Ri
B.	(1 – Ro) = Ro/Ri
C.	(1 + Ri) = Ro/Ri
D.	(1 – Ri) = Ro/Ri
Answer» B. (1 – Ro) = Ro/Ri

223.	Penetration theory states that the mass transfer co-coefficient is equal to (where, De is diffusivity and ‘t’ is time) ?
A.	(De.t)1/2
B.	(De/t)1/2
C.	(4De/πt)1/2
D.	(4De/t)
Answer» D. (4De/t)

224.	Penetration theory relates the average mass transfer co-efficient (K) with diffusivity D. as____________________?
A.	K ∝D
B.	K ∝√D
C.	K ∝D1.5
D.	K ∝D2
Answer» C. K ∝D1.5

212.	Pick out the wrong statement pertaining to the rotary dryer ?
A.	Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it down through the current of hot air/gases. It extend
B.	Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at any instant. The best performance for rotary drier i
C.	Rotary dryer is suitable for drying sticky material
D.	Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute
Answer» D. Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute

213.	Pick out the wrong statement pertaining to leaching ?
A.	Fine solids cannot be leached in a Pachuca tank
B.	Door classifier can be used for leaching of coarse solids
C.	Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor
D.	Very high temperature is not needed for the leaching of sugar beet
Answer» B. Door classifier can be used for leaching of coarse solids

214.	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.

215.	Pick out the wrong statement pertaining to the analogy between equations of heat and mass_________________?
A.	Sherwood number in mass transfer is analogous to Nusselt number in heat transfer
B.	Prandtl number in heat transfer is analogous to Schmidt number in mass transfer
C.	Reynolds number in mass transfer is analogous to Grashoff number in heat transfer
D.	Reynolds number remains the same in both heat and mass transfer
Answer» D. Reynolds number remains the same in both heat and mass transfer

216.	Pick out the wrong statement. Generally for physical adsorption, a gas of________________?
A.	Higher molecular weight is adsorbed in preference to a gas of low molecular weight
B.	High critical temperature is adsorbed in preference to a gas of low critical temperature
C.	Low volatility is adsorbed in preference to a gas of high volatility
D.	None of these
Answer» E.

219.	Physical absorption is__________________?
A.	An irreversible phenomenon
B.	A reversible phenomenon
C.	Accompanied by evolution of heat
D.	Both B. and C.
Answer» E.

220.	pertaining to the analogy between equations of heat and mass transfer operations ?_x005F_x000D_Pick out the wrong statement
A.	Sherwood number in mass transfer is analogous to Nusselt number in heat transfer
B.	Prandtl number in heat transfer is analogous to Schmidt number in mass transfer
C.	Reynolds number in mass transfer is analogous to Grashoff number in heat transfer
D.	Reynolds number remains the same in both heat and mass transfer
Answer» D. Reynolds number remains the same in both heat and mass transfer

221.	Perforated plate towers are unique for solvent extraction because, they provide_____________________?
A.	Higher contact area
B.	Better contact of the phase
C.	Repeated coalescence & redispersion of the drop phase
D.	None of these
Answer» D. None of these

222.	Percentage saturation is _______________ the relative saturation?
A.	Always smaller than
B.	Always greater than
C.	Not related to
D.	None of these
Answer» B. Always greater than

225.	Penetration model (theory) for mass transfer was enunciated by _____________________?
A.	Danckwerts
B.	Toor and Marcello
C.	Higbie
D.	Kissinevskii
Answer» D. Kissinevskii

Explore topic-wise MCQs in Chemical Engineering.

Prandtl number for water at 20°C is about ________________?

Powdery materials can be guarded against caking tendency on storage by_________________?

Powdery materials can be guarded against caking tendency on storage by___________________?

Positive deviation from Raoult’s law means a mixture whose total pressure is___________________?

Pore size of the molecular sieve 5A is ____________________ mm ?

Ponchon-Savarit method analyses the fractional equipment based on___________________?

Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the____________________?

Plate efficiency_______________________?

Plate efficiency in a distillation column is reduced due to the ______________________ of liquid?

Plate efficiency in a distillation column is reduced due to the ______________ of liquid?

Pick out the wrong statement. Raoult’s law does not apply, when the______________________?

Pick out the wrong statement pertaining to the rotary dryer ?

Pick out the wrong statement pertaining to leaching ?

Pick out the wrong statement pertaining to the cooling towers ?

Pick out the wrong statement pertaining to the analogy between equations of heat and mass_________________?

Pick out the wrong statement. Generally for physical adsorption, a gas of________________?

Pick out the system with minimum boiling azeotrope at 1 atm ?

Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.) ?

Physical absorption is__________________?

pertaining to the analogy between equations of heat and mass transfer operations ?_x005F_x000D_Pick out the wrong statement

Perforated plate towers are unique for solvent extraction because, they provide_____________________?

Percentage saturation is _______________ the relative saturation?

Penetration theory states that the mass transfer co-coefficient is equal to (where, De is diffusivity and ‘t’ is time) ?

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

Penetration model (theory) for mass transfer was enunciated by _____________________?

Paper industry employs _______________ driers?

Paper industry employs _____________ driers ?

Packed column distillation is limited to the column _____________ metres?

Overall efficiency of the distillation column is _____________________?

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_________________?

Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in ______________ tower?

Ordinary diffusion process is also called ______________ diffusion?

Operating velocity in a packed tower is usually __________________ the flooding velocity ?

Only small amount of evaporation of water produces large cooling effects because of its___________________?

One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect ?

On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in______________________?

On addition of solute in the solvent, the ______________ of the solution decreases ?

Occurrence of ‘case hardening’ during drying of a high moisture solid cake _______________ the drying rate?

_______________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower?

(NSh/NRe.NSc) is termed in mass transfer operation as the __________________________?

NSc/NPr is called the______________________?

(NRe . NSc) is termed in mass transfer operation as the ______________ number?

Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure. Nitrobenzene will distil off _______________ °C?

Most important factor to be considered in the selection of packings for absorbers is the ______________ of packing?

Molecular sieves are regenerated by heating to ______________ °C?

Molecular sieves are porous____________________?

Molecular distillation is_____________________?

Molecular diffusivity of a liquid__________________?

Molecular diffusion is caused by the________________?

Molarity is defined as the number of gm moles of solute per ________________ of solvent?

226.	Paper industry employs _______________ driers?
A.	Cylinder
B.	Rotary
C.	Spray
D.	Fluidised bed
Answer» B. Rotary

227.	Paper industry employs _____________ driers ?
A.	Cylinder
B.	Rotary
C.	Spray
D.	Fluidised bed
Answer» B. Rotary

228.	Packed column distillation is limited to the column _____________ metres?
A.	Height < 6
B.	Diameter < 0.6
C.	Both A. & B.
D.	Neither A. nor B.
Answer» D. Neither A. nor B.

229.	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

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

231.	Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in ______________ tower?
A.	Wetted wall
B.	Bubble cap
C.	Perforated tray
D.	Packed
Answer» B. Bubble cap

232.	Ordinary diffusion process is also called ______________ diffusion?
A.	Pressure
B.	Thermal
C.	Concentration
D.	Forced
Answer» D. Forced

233.	Operating velocity in a packed tower is usually __________________ the flooding velocity ?
A.	Half
B.	Twice
C.	Equal to
D.	More than
Answer» B. Twice

234.	Only small amount of evaporation of water produces large cooling effects because of its___________________?
A.	Large latent heat
B.	Low viscosity
C.	Small latent heat
D.	None of these
Answer» B. Low viscosity

235.	One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect ?
A.	The product composition but not the fraction vaporised
B.	The product composition as well as the fraction vaporised
C.	The fraction vaporised but not the product composition
D.	Neither the product composition nor the fraction vaporised
Answer» D. Neither the product composition nor the fraction vaporised