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 4 of 12

Q31.
Estimate the diffusion coefficient of carbon monoxide through air in which the mole fractions of each constituents are
O₂ = 0.18

N₂ = 0.72

CO = 0.10

The gas mixture is at 300 K and 2 atmosphere total pressure. The diffusivity values are

D CO = 18.5 * 10⁻⁶ m²/s at 273 K, 1 atm

D CN = 19.2 * 10⁻⁶ m²/s at 288 K, 1 atm

The C is carbon monoxide, O is oxygen and N is nitrogen.
Discuss
Answer: (a).10.29 * 10⁻⁶ m²/s
Q32.
What is the molecular weight of Sulphur-dioxide?
Discuss
Answer: (c).64
Q33.
The dimension of diffusion coefficient is given by
Discuss
Answer: (b).L² T⁻¹
Q34.
For what kind of mixtures Dᴀв=Dвᴀ holds?
Discuss
Answer: (a).Ideal
Q35.
In the expression for molar flux Nᴀ=(Nᴀ+Nв)Cᴀ/C – DᴀвdCᴀ/dz, the terms representing bulk flow and molecular diffusion are, respectively
Discuss
Answer: (b).(Nᴀ+Nв)Cᴀ/C, DᴀвdCᴀ/dz
Q36.
Consider loss of ethanol vapor by diffusion from a half-filled open test tube. At what point in the diffusion path will the contribution of the bulk flow term to the molar flux be maximum?
Discuss
Answer: (a).At the liquid-gas interface
Q37.
A reaction 3A+2B+C=1.5D+E occurs in a reactor at steady state. What will be the value of the flux ratio Nᴀ/Nᴅ
Discuss
Answer: (a).-2
Q38.
For a component A of a mixture, concentration as a function of x is given:

Cᴀ=5e⁻¹⁰ˣ (x is in cm and Cᴀ in mol/liter)

Calculate the value of diffusion velocity (m/s) of the component A at the point x=0, if diffusivity of A in the mixture is 2.567*10⁻⁵m²/s.
Discuss
Answer: (a).0.2567
Q39.
A sheet of Fe 1.0 mm thick is exposed to an oxidizing gas on one side and a deoxidizing gas on the other at 725°C. After reaching steady state, the Fe membrane is exposed to room temperature, and the C concentrations at each side of the membrane are 0.012 and 0.075 wt%. Calculate the diffusion coefficient (m²/sec) if the diffusion flux is 1.4×10⁻⁸kg/m²-sec.
Discuss
Answer: (a).9.87*10⁻¹²
Q40.
At which condition molar flux with respect to a stationary observer and with respect to an observer moving with molar average velocity?
Discuss
Answer: (a).In a very dilute solution
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