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Interview MCQ Set 1

1. Which of the following changes does not induce precipitation?
a) pH
b) Temperature
c) Addition of salts
d) Gravity

View Answer

Answer: d [Reason:] Gravity does not induce precipitation.

2. What is a special case of precipitation?
a) Distillation
b) Fractional distillation
c) Sedimentation
d) Crystallization

View Answer

Answer: d [Reason:] Crystallization is a special case of precipitation where the produc is crystallized and produced slowly under very controlled conditions.

3. Why is the pH change to induce precipitation not useful for commercialization?
a) Proteins do not precipitate easily
b) The minimum pH is unknown
c) There are large differences in the isoelectric points
d) Carrying a pH meter is not helpful

View Answer

Answer: c [Reason:] The pH change to induce precipitation not useful for commercialization because there are large differences in the isoelectric points.

4. How does the salting out mechanism not occur?
a) Salt removes water by associating with water molecules
b) Few amount of water is left for proteins
c) Shielding the electrostatic protein-protein changes that account for protein-protein repulsion
d) Creating a barrier between the proteins and water

View Answer

Answer: d [Reason:] The salting out mechanism occurs partly because salt removes water by associating with water molecules and partly by shielding the electrostatic protein-protein changes that account for protein-protein repulsion.

5. When are organic solvents not commonly used for precipitation?
a) DNA precipitation
b) RNA precipitation
c) Plasma-protein precipitation
d) Protein separation

View Answer

Answer: d [Reason:] The organic solvents ethanol and acetone are used for, DNA, RNA and plasma-protein precipitation.

6. How is the physical process of sedimentation not enhanced?
a) Coagulation
b) Flocculation
c) Agglomeration
d) Decantation

View Answer

Answer: d [Reason:] Decantation does not enhance sedimentation whereas coagulation and flocculation do.

7. How is flocculation defined as?
a) Further agglomeration of small, slowly settling floc formed during coagulation to form a larger floc
b) Cause (a fluid) to change to a solid or semi-solid state
c) Gradually pour (wine, port, or another liquid) from one container into another, typically in order to separate out sediment
d) Deagglomeration to break into smaller particles

View Answer

Answer: a [Reason:] Flocculation is defined as further agglomeration of small, slowly settling floc formed during coagulation to form a larger floc.

8. Which particles have the largest diameter?
a) Colloidal
b) Flocculated
c) Coagulated
d) Dispersed

View Answer

Answer: b [Reason:] The flocculated particles have the largest diameter from 1-10 millimeters.

9. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 95%
Maximum concentration C= 10
Calculate the time required
a) 2344s
b) 4345s
c) 2345s
d) 4028s

View Answer

Answer: d [Reason:] Since c/C= (1-exp(-t/T)n, hence t=4028s.

10. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 0.85%
Maximum concentration C= 10
Calculate the time required
a) 2344s
b) 4345s
c) 2500s
d) 4028s

View Answer

Answer: c [Reason:] Since c/C= (1-exp(-t/T)n, hence t=2500s.

11. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 0.89%
Maximum concentration C= 10
Calculate the time required
a) 2000s
b) 2500s
c) 3000s
d) 3400s

View Answer

Answer: c [Reason:] Since c/C= (1-exp(-t/T)n, hence t=3000s.

12. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 77%
Maximum concentration C= 10
Calculate the time required
a) 2000s
b) 2500s
c) 3000s
d) 3400s

View Answer

Answer: a [Reason:] Since c/C= (1-exp(-t/T)n, hence t=2000s.

13. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 92%
Maximum concentration C= 10
Calculate the time required
a) 3100s
b) 3200s
c) 3300s
d) 3400s

View Answer

Answer: d [Reason:] Since c/C= (1-exp(-t/T)n, hence t=3400s.

14. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 87.5%
Maximum concentration C= 10
Calculate the time required
a) 2344s
b) 4566s
c) 2800s
d) 4454s

View Answer

Answer: c [Reason:] Since c/C= (1-exp(-t/T)n, hence t=2800s.

15. If the passes through the device is n=1
The time constant T=1345s
Expected release percent= 83%
Maximum concentration C= 10
Calculate the time required
a) 2344s
b) 4345s
c) 2345s
d) 4028s

View Answer

Answer: c [Reason:] Since c/C= (1-exp(-t/T)n, hence t=2345s.

Interview MCQ Set 2

1. What is the definition of melt crystallization?
a) Crystallization of melts from eutectic-forming or solid solution forming mixtures
b) Crystallization of melts from eutectic-forming or liquid solution forming mixtures
c) Crystallization of melts from eutectic-forming or constant boiling mixtures
d) Crystallization at very high temperatures

View Answer

Answer: a [Reason:] Crystallization of melts from eutectic-forming or solid solution forming mixtures is called as melt crystallization.

2. What are the two major methods for melt crystallization?
a) Suspension, layer
b) Layer, multilayer
c) Suspension, colloidal
d) Layer, non-layer

View Answer

Answer: a [Reason:] The two types of melt crystallization are suspension crystallization and melt crystallization.

3. If Kc=10
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=2
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 20
b) 22.4
c) 25.6
d) 27.8

View Answer

Answer: b [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 22.4.

4. If Kc=10
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=4
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 14.6
b) 15.63
c) 15.81
d) 27.2

View Answer

Answer: b [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 15.81.

5. If Kc=10
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=2
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 12.9
b) 15.7
c) 19.5
d) 27.8

View Answer

Answer: a [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 12.9.

6. If Kc=20
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=2
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 25.6
b) 29.4
c) 31.6
d) 72.5

View Answer

Answer: c [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 31.6.

7. If Kc=30
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=2
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 31.6
b) 34.6
c) 36.7
d) 38.7

View Answer

Answer: d [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 38.7.

8. If Kc=20
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=4
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 20
b) 22.4
c) 25.6
d) 27.8

View Answer

Answer: b [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 22.4.

9. If Kc=40
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=2
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 34.6
b) 39.6
c) 44.7
d) 78.4

View Answer

Answer: c [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 44.7.

10. If Kc=30
Temperature difference Tm-Tc=50
Time taken = 3000s
Density d=4
Rate of heat released by freezing =1000
Calculate the crystal thickness
a) 20
b) 22.4
c) 25.6
d) 27.38

View Answer

Answer: b [Reason:] Since crystal thickness= sqrt(2*( Tm-Tc)Kct/dH), hence crystal thickness= 27.38.

Interview MCQ Set 3

1. By which reaction are synthetic polymers not made?
a) Condensation
b) Free radical addition
c) Ion-catalyzed addition
d) Hydroxylation

View Answer

Answer: d [Reason:] Hydroxylation reaction cannot make a polymer or cannot form a long chain, hence not used to make synthetic polymer.

2. What are the linear chain polymers that get soften on increase in temperature?
a) Thermosetting
b) Thermoplastic
c) Crystalline
d) Amorphous

View Answer

Answer: b [Reason:] The thermoplastic polymers are linear chain polymers which are soluble in organic solvents and soften upon increase in temperature.

3. Which of the following is not a property of thermosetting polymer?
a) Highly crosslinked
b) Decompose on increase in temperature
c) Insoluble in organic solvents
d) Amorphous

View Answer

Answer: d [Reason:] Thermosetting polymers may or may not be amorphous. Hence it is not a property of a thermosetting polymer.

4. What is a glass transition temperature?
a) When a rubbery polymer turns into glass
b) When a glassy polymers turns into rubbery polymer
c) When the polymer becomes a melt
d) When the melting point is reached

View Answer

Answer: b [Reason:] When the temperature of a glassy polymer is reached a certain temperature known as glass transition temperature is achieved where the polymer turns rubbery.

5. The reaction product of cellulose and acetic anhydride is:
a) Acetic cellulose
b) Cellulose acetate
c) Cellulose diacetate
d) Cellulose triacetate

View Answer

Answer: d [Reason:] The reaction of product of cellulose and acetic anhydride is cellulose triacetate which is hydrophobic, highly crystalline and high quality.

6. To increase the strength of polyisoprene ,it is vulcanized with:
a) Rubber
b) Phosphorous
c) Sulphur
d) Sodium

View Answer

Answer: c [Reason:] Vulcanization is done with the help of sulphur, a process that introduces crosslinks.

7. Which of the following is not a property of aromatic polyamides?
a) Low melting
b) Crystalline
c) High resistance to solvents
d) Long term thermal stability

View Answer

Answer: a [Reason:] Aromatic polyamides are high melting crystalline polymers.

8. Which of the following true about polycarbonates?
a) Amorphous
b) Not ductile
c) Fragile
d) Thermosetting

View Answer

Answer: a [Reason:] Polycarbonates which are characterized by –OCOO- chain are amorphous polymers.

9. Polysulphones contain the _______ group.
a) S
b) CO
c) SO2
d) SO4

View Answer

Answer: c [Reason:] Polysulphones can be easily made into fibres and all of them contain a SO2 group.

10. Which of the following is untrue about Polytetrafluoroethylene?
a) Branched chain
b) Highly crystalline
c) Exceptional thermal stability
d) High degree of polymerization

View Answer

Answer: a [Reason:] Polytetrafluoroethylene is a straight chain polymer and can be formed into films and tubing.

Interview MCQ Set 4

1. At what temperature is film stretching done?
a) Room temperature
b) Melting point of polymer
c) 100oc
d) 200oc

View Answer

Answer: b [Reason:] Film stretching is done at melting point of polymer.

2. Which method is not employed in preparation of asymmetric membrane?
a) Precipitation by cooling
b) Track etching
c) Precipitation by evaporation
d) Precipitation by immersion in a solvent

View Answer

Answer: b [Reason:] Track etching is not used in making asymmetric membranes.

3. What is a composite membrane?
a) Same as symmetric membrane
b) Same as asymmetric membrane
c) Asymetric membrane cast on a support
d) Two types of membrane are together

View Answer

Answer: c [Reason:] A composite membrane functions like a asymmetric membrane but it is cast on a solid support.

4. Ceramic membrane is a type of:
a) Polymeric membrane
b) Liquid membrane
c) Inorganic membrane
d) Gas membrane

View Answer

Answer: c [Reason:] Ceramic membrane is a type of inorganic membrane.

5. Microporous membrane s a type of
a) Ceramic membrane
b) Liquid membrane
c) Polymeric membrane
d) Inorganic membrane

View Answer

Answer: c [Reason:] Microporous membrane is a type of polymeric membrane.

6. What is the molar transmembrane flux of species if
Premeability P= 10 units
Membrane thickness l= 10units
Driving force = 500units
a) 500
b) 200
c) 400
d) 600

View Answer

Answer: a [Reason:] Since P/l(driving force)= N, hence N= 500.

7. What is the molar transmembrane flux of species if
Premeability P= 10 units
Membrane thickness l= 5units
Driving force = 500units
a) 500
b) 200
c) 400
d) 1000

View Answer

Answer: d [Reason:] Since P/l(driving force)= N, hence N= 1000.

8. What is the molar transmembrane flux of species if
Premeability P= 10 units
Membrane thickness l= 10units
Driving force = 200units
a) 500
b) 200
c) 400
d) 600

View Answer

Answer: b [Reason:] Since P/l(driving force)= N, hence N= 200.

9. What is the molar transmembrane flux of species if
Premeability P= 50 units
Membrane thickness l= 10units
Driving force = 100units
a) 5000
b) 2005
c) 4003
d) 6000

View Answer

Answer: a [Reason:] Since P/l(driving force)= N, hence N= 5000.

10. What is the molar transmembrane flux of species if
Premeability P= 10 units
Membrane thickness l= 100units
Driving force = 700units
a) 500
b) 20
c) 40
d) 70

View Answer

Answer: d [Reason:] Since P/l(driving force)= N, hence N= 70.

Interview MCQ Set 5

1. What is a membrane module?
a) A membrane module is a representation of the type of pores in a membrane
b) A membrane module is a unit housing the membrane
c) A membrane is representation of an ideal membrane
d) A membrane module is representation of the concentration changes during separation

View Answer

Answer: b [Reason:] A membrane module is a unit housing the membrane and its arrangement.

2. What is the use of cross flow in plate and frame module?
a) Reduces fouling
b) Reduces loss
c) Reduces efficiency
d) Increases efficiency

View Answer

Answer: a [Reason:] Cross flow ensures that there is less fouling.

3. What is the packing density of plate and frame module?
a) 100-400m2/m3
b) 500-100m2/m3
c) 200-400 m2/m3
d) 500-1000 m2/m3

View Answer

Answer: a [Reason:] The packing density of plate and frame module is 100-400 m2/m3.

4. What is the packing density of spiral-wound module?
a) 100ft2/ft3
b) 200 m2/m3
c) 400 m2/m3
d) 1000 m2/m3

View Answer

Answer: a [Reason:] The packing density if spiral-wound module is 100ft/ft3.

5. Which membrane module represents a spiral heat exchanger?
a) Plate and frame module
b) Spiral wound module
c) Hollow fibre module
d) No module exists

View Answer

Answer: b [Reason:] A spiral wound module represents a spiral heat exchanger.

6. What is the life spiral-wound module?
a) 2 months
b) 10years
c) 2-3 years
d) 5-9 years

View Answer

Answer: c [Reason:] The life of spiral wound module is 2-3 years.

7. What is the packing density of hollow-fibre module?
a) 200 ft2/ft3
b) 4000 ft2/ft3
c) 5000 ft2/ft3
d) 10000 ft2/ft3

View Answer

Answer: d [Reason:] The hollow fibre module has high packing density of about 10000ft2/ft3.

8. Why is there a chance of fouling in hollow fibre module?
a) Fibres form a bundle and there is little free space
b) High packing density
c) Narrow pores
d) Excessive density of membrane material

View Answer

Answer: a [Reason:] The hollow fibre membranes is sensitive to fouling as fibres form a bundle and there is little free space.

9. What is the alternate feed and permeate regions in plate and frame modules called as?
a) Spacers
b) Stop disk
c) Tie rod
d) Channel

View Answer

Answer: a [Reason:] The alternate feed and permeate regions in plate and frame modules are called as spacers.

10. Which module is preferred for reverse osmosis operation?
a) Hollow fibre module
b) Plate and frame module
c) Spiral wound module
d) No module is used

View Answer

Answer: c [Reason:] Spiral wound module is used for reverse osmosis operations.