Explore topic-wise MCQs in Mass Transfer.

This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Mass Transfer knowledge and support exam preparation. Choose a topic below to get started.

1.

In sulphuric acid plants dry air is used for burning of sulphur. Air is dried in contact with concentrated Sulphuric acid. Moisture diffuses through a layer of air, reaches the surface and gets absorbed in it. Here air is said to be non-diffusing were as moisture is diffusing. Which of the following statements are correct?

A. Moisture has a source and a sink whereas dry air has a source but no sink
B. Moisture as well as dry air have a sink
C. Moisture has a source but no sink whereas dry air has a source as well as sink
D. Moisture as well as dry sir have no sink
Answer» B. Moisture as well as dry air have a sink
Discussion
2.

The value of a ratio of N flux of A to the total N flux for a steady state equimolar counter diffusion is

A. 0
B. Infinity
C. 1
D. None of the mentioned
Answer» C. 1
Discussion
3.

For a steady state equimolar counter diffusion of A and B. The N flux of A is ________

A. – N flux of A
B. N flux of A
C. – N flux of B
D. N flux of B
Answer» D. N flux of B
Discussion
4.

What is the value of the flux (kmol/m3.s) of water vapor through a stagnant film of estimated thickness 1.5mm on the water surface?

A. 1.36*10-5
B. 1.96*10-5
C. 1.96*10-1
D. 1.96*10-7
Answer» C. 1.96*10-1
Discussion
5.

What will be the values of the diffusivities (in cm2/s) at the mean gas-film temperature?

A. 0.923,0.267
B. 0.483,1.351
C. 0.294,0.368
D. 1.381,0.364
Answer» B. 0.483,1.351
Discussion
6.

A mixture undergoing multicomponent diffusion is analyzed through the Maxwell-Stefan approach. With regard to this approach which among the following statements are incorrect? The difference in the partial pressure of the Component A over a small distance ∆z (AB)is proportional to

A. The molar concentration at the two points
B. Length of the diffusion path
C. Velocity at the point A
D. Difference in the velocities at point A and B
Answer» D. Difference in the velocities at point A and B
Discussion
7.

For a steady state equimolar counter diffusion of A and B. The N flux of A is _______?

A. – N flux of A
B. N flux of A
C. – N flux of B
D. N flux of B
Answer» B. N flux of A
Discussion
8.

What is the value of the flux (kmol/m3.s) of water vapor through a stagnant film of estimated thickness 1.5mm on the water surface?

A. 1.36*10<sup>-5</sup>
B. 1.96*10<sup>-5</sup>
C. 1.96*10<sup>-1</sup>
D. 1.96*10<sup>-7</sup>
Answer» C. 1.96*10<sup>-1</sup>
Discussion
9.

What will be the values of the diffusivities (in cm2/s) at the mean gas-film temperature?

A. 0.923,0.267
B. 0.483,1.351
C. 0.294,0.368
D. 1.381,0.364
Answer» D. 1.381,0.364
Discussion
10.

If all the components except 1 of the multicomponent diffusing mixture are inert, then what will be the expression for Diffusivity of component 1 in the mixture?

A. D<sub>1m</sub>=(N<sub>1</sub>-Y<sub>1</sub>‚àëN<sub>j</sub>)/(‚àë(Y<sub>j</sub>N<sub>1</sub>-Y<sub>1</sub>N<sub>j</sub>)/D<sub>ij</sub>)
B. D<sub>1m</sub>=(Y<sub>1</sub>‚àëN<sub>j</sub>)/(‚àë(Y<sub>j</sub>N<sub>1</sub>-Y<sub>1</sub>N<sub>j</sub>)/D<sub>ij</sub>)
C. D<sub>1m</sub>=N<sub>1</sub>/(‚àë[(Y<sub>j</sub>N<sub>1</sub>-Y<sub>1</sub>N<sub>j</sub>)/D<sub>ij</sub>])
D. D<sub>1m</sub>=(1-Y<sub>1</sub>)/(‚àë[Y<sub>j</sub>/D<sub>ij</sub>])
Answer» E.
Discussion
11.

A mixture undergoing multicomponent diffusion is analyzed through the Maxwell-Stefan approach. With regard to this approach which among the following statements are incorrect? The difference in the partial pressure of the Component A over a small distance ∆z (AB)is proportional to

A. The molar concentration at the two points
B. Length of the diffusion path
C. Velocity at the point A
D. Difference in the velocities at point A and B
Answer» D. Difference in the velocities at point A and B
Discussion