Modes and Diffusion MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Modes and Diffusion, a fundamental topic in the field of Mass Transfer. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our Modes and Diffusion 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 Modes and Diffusion mcq questions that explore various aspects of Modes and Diffusion problems. Each MCQ is crafted to challenge your understanding of Modes and Diffusion principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace Mass Transfer tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our Modes and Diffusion MCQs are your pathway to success in mastering this essential Mass Transfer topic.

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Modes and Diffusion MCQs | Page 3 of 12

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Q21.
A molecule in a mixture moves with a velocity of 0.03m/s in (+x) direction. The concentration of the particle is 0.5 mol/liter. A observer is running in (-x) direction with a velocity of 2m/s. calculate the value of molar flux (mol/m².s) relative to the observer.

a.

0.015

b.

15

c.

1.015

d.

1015

Discuss
Answer: (d).1015
Q22.
A molecule in a mixture moves with a velocity of 0.03m/s in (+x) direction. The concentration of the particle is 0.5 mol/liter. A observer is running in (-x) direction with a velocity of 2m/s. What will be the value of flux (mol/m².s) with respect to a stationary observer?

a.

0.015

b.

15

c.

1.015

d.

1015

Discuss
Answer: (b).15
Q23.
Under which of the following conditions mass average velocity and molar average velocity are equal?

a.

In a very dilute solution

b.

If molecular weights of all the species are equal

c.

Always different

d.

In dilute solutions as well as in solutions in which all components have same molecular weights

Discuss
Answer: (d).In dilute solutions as well as in solutions in which all components have same molecular weights
Q24.
The mass flow rate of a component in a mixture in X-direction is 2kg/s. The area vector at a particular cross-section is (1.1, 3.2, 5.4) cm². Calculate the value of flux (kg/cm².s) through the cross-section.

a.

0.31

b.

2.2

c.

1.82

d.

6.45

Discuss
Answer: (c).1.82
Q25.
Fick’s law is given by the formula

a.

N b = – D b c d C b/d x

b.

N b = – 2 D b c d C b/d x

c.

N b = – 3 D b c d C b/d x

d.

N b = – 4 D b c d C b/d x

Discuss
Answer: (a).N b = – D b c d C b/d x
Q26.
What is the unit of diffusion coefficient?

a.

m²

b.

s

c.

m² s

d.

m²/s

Discuss
Answer: (d).m²/s
Q27.
What is the molecular weight of ammonia?

a.

31

b.

53

c.

29

d.

39

Discuss
Answer: (c).29
Q28.
What is the molecular volume of air at normal boiling point?

a.

29.89 cm³/gm mole

b.

39.89 cm³/gm mole

c.

49.89 cm³/gm mole

d.

59.89 cm³/gm mole

Discuss
Answer: (a).29.89 cm³/gm mole
Q29.
What is the value of Schmidt number for hydrogen?

a.

0.23

b.

0.22

c.

0.21

d.

0.21

Discuss
Answer: (b).0.22
Q30.
Estimate the diffusion coefficient for ammonia in air t 25 degree Celsius temperature and one atmospheric pressure.

For ammonia,

Molecular weight = 17
Molecular volume = 25.81 cm³/gm mole

For air,
Molecular weight = 29

a.

0.4880 cm²/s

b.

0.3880 cm²/s

c.

0.2880 cm²/s

d.

0.1880 cm²/s

Discuss
Answer: (d).0.1880 cm²/s
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