Agitation and Aeration MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Agitation and Aeration, a fundamental topic in the field of Biochemical Engineering. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our Agitation and Aeration MCQs are designed to help you grasp the core concepts and excel in solving problems.

In this section, you'll find a wide range of Agitation and Aeration mcq questions that explore various aspects of Agitation and Aeration problems. Each MCQ is crafted to challenge your understanding of Agitation and Aeration principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace Biochemical Engineering tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our Agitation and Aeration MCQs are your pathway to success in mastering this essential Biochemical Engineering topic.

Note: Each of the following question comes with multiple answer choices. Select the most appropriate option and test your understanding of Agitation and Aeration. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

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Agitation and Aeration MCQs | Page 4 of 11

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Q31.
The rate limiting step in the movement of oxygen from the gas phase in a bubble to the cell is the movement of oxygen molecules through

a.

gas-liquid interface

b.

bubble boundary layer

c.

bulk liquid

d.

gas phase

Discuss
Answer: (b).bubble boundary layer
Q32.
Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (te). The model correlating KL, mass transfer coefficient and DAB, diffusivity can be expressed as

a.

KL = 2(DAB/Ο€te)^0.25

b.

KL = 2(DAB/Ο€te)^0.5

c.

KL = 2(DAB/Ο€te)^0.75

d.

KL = 2(DAB/Ο€te)

Discuss
Answer: (b).KL = 2(DAB/Ο€te)^0.5
Q33.
The oxygen uptake requirements of a microbial population is characterized by the following parameters: ΞΌm = 0.2 h­¹, K0 = 0.2 mg Oβ‚‚.l­¹, Y0 = 0.5 mg dry weight/mg Oβ‚‚ and C0,crit=0.8 mg.l­¹ The required concentration of cells is 1000 mg.l­¹ and the saturation oxygen concentration of the medium is 5.8 mg.l­¹. The required KLa must be greater than

a.

64 h­¹

b.

32 h­¹

c.

16 h­¹

d.

8h­¹

Discuss
Answer: (a).64 h­¹
Q34.
Which have the maximum resistance while transferring carbon dioxide from the bulk liquid to an air bubble?

a.

Moving through the gas liquid interface

b.

Moving through the bubble boundary layer

c.

Moving across the cell membrane

d.

Moving through the bulk liquid

Discuss
Answer: (b).Moving through the bubble boundary layer
Q35.
If liquid density and viscosity remains constant, then the Reynolds number in a stirred tank reactor will vary with the

a.

impeller diameter

b.

square root of the impeller diameter

c.

square of the impeller diameter

d.

cube of the impeller diameter

Discuss
Answer: (c).square of the impeller diameter
Q36.
Power number is ratio of

a.

imposed forced to intertial force

b.

bouyant force to inertial force

c.

gravitation force to inertial force

d.

imposed force to gravitational force

Discuss
Answer: (a).imposed forced to intertial force
Q37.
The volume of liquid (VL) in a cylindrical reactor can be calculated from the liquid height (HL) and tank diameter (Dt) using the following equation

a.

VL = 4/3 x Ο€ x HL x Dt³/8

b.

VL= HL x Ο€ x Dt²/4

c.

VL= HL x Ο€ x Dt²

d.

VL = 4 x Ο€ x Dt²

Discuss
Answer: (b).VL= HL x Ο€ x Dt²/4
Q38.
The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)

a.

H = (Zf-Zl)/Zf

b.

H = Zf/Zl

c.

H = Zf/ZfZl

d.

H =(Zf+Zl)/Zf

Discuss
Answer: (a).H = (Zf-Zl)/Zf
Q39.
Which of the following(s) is/are non-mechanically agitated reactors?

a.

Stirrer tank reactor

b.

Bubble column

c.

Air lift reactor

d.

Both (b) and (c)

Discuss
Answer: (d).Both (b) and (c)
Q40.
Which of the following best explains the reasons for using axial flow impellers in crystallization and precipitation reactions?

a.

Crystal and precipitates are not too small, so as to ensure easy separation of the solids from the mother liquor

b.

Crystals and precipitates are thoroughly broken down, so as to ensure easy separation of the solids from the mother liquor

c.

Both (a) and (b)

d.

Axial flow impellers provide low shear, energy efficient mixing conditions

Discuss
Answer: (a).Crystal and precipitates are not too small, so as to ensure easy separation of the solids from the mother liquor
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