Mass Transfer Multiple Choice Questions on “Extraction Equipments”.
1. __________ is the single stage device in extractor types.
a) Mixer settler
b) Sieve trays
c) Agitator vessel
d) Packed column
Answer: a
Clarification: Mixer-settler is a single stage device used for extraction operation.
2. Settler in the mixer settler is applicable for rapid agitation.
a) True
b) False
Answer: a
Clarification: Settler is used for settling.
3. The substance to get mixed enters into the mixer through.
a) Orifice
b) Nozzle
c) Orifice or nozzle
d) None of the mentioned
Answer: c
Clarification: Orifice or nozzle both are used for allowing the substance into the mixer.
4. Line mixers are ________
a) Small
b) Large
c) Very high
d) None of the mentioned
Answer: a
Clarification: Line mixers or flow mixers are used inside pipes so it must be small.
5. The two liquids while mixing gets dispersed inside the mixer.
a) True
b) False
Answer: a
Clarification: Due to the loss of energy by pressure drop the liquids gets dispersed inside the mixer.
6. If the holding time is more in a mixer then _______ will be poor.
a) Mass transfer
b) Heat transfer
c) Momentum transfer
d) Both mass and momentum transfer
Answer: a
Clarification: If the holding of liquids inside the mixer is poor then the rate of mass transfer gets decrease.
7. More than three stages of mixer settler attached to get _____________
a) Multi-component cascade
b) Mixer settler cascade
c) Extraction multi-stages
d) None of the mentioned
Answer: b
Clarification: Generally two or more stages inter connected to form cascades so it is an mixer settler cascades.
8. The extractor preferred for getting immediate dispersion after piping is ___________________
a) Don extractor
b) Box extractor
c) Boltzmann extractor
d) Immediate dispersion is not possible
Answer: b
Clarification: The box arrangement of alternate stages produces immediate dispersion.
9. If a system has low interfacial tension _________ extractor is preferred.
a) Packed column
b) Pulse column
c) Sieve plates
d) Agitator column
Answer: c
Clarification: For a system with low interfacial tension need not need mechanical agitation so sieve plates are preferred.
10. _____________ mixing is applicable for differential contractors.
a) Axial
b) Radial
c) Both axial and radial
d) None of the mentioned
Answer: a
Clarification: Due to the reduction of concentration difference between the phases axial mixing is preferred.
11. Packed tower with ________ packing preferable for liquid extraction.
a) Uniform
b) Random
c) Complete
d) None of the mentioned
Answer: b
Clarification: To reduce axial mixing random packing are preferred in a packed column.
12. Motivational force in a differential contractor is
a) Centrifugal force
b) Gravitational force
c) Electromagnetic forces
d) All of the mentioned
Answer: b
Clarification: In extractor the light liquid enters the bottom and also the extractor is vertical so gravitational force is a motivational force.
13. The high density difference among the liquid in the extractor cause ________
a) Flooding
b) Loading
c) Agitation
d) None of the mentioned
Answer: a
Clarification: Generally, the density difference leads to separation from each other which results in flooding.
14. Differential contractors are continuous extractor.
a) True
b) False
Answer: a
Clarification: Differential contractor was named because of continuous contact of entering and leaving streams.
15. Find the process.
a) Batch process
b) Continuous process
c) Batch+ continuous process
d) None of the mentioned
Answer: c
Clarification: Mixer is a batch process and settler is a continuous process.