Questions and answers for exam Preparation

MCQs

Total Questions : 71 | Page 5 of 8 pages

Question 41. Find the flux of A ( xA= 0.2) if Total flux is 5 mol/sq.m sec and J flux of A is 2 mol/sq.m sec.

Discuss Question

Answer: Option C. -> 3
Answer: (c).3

Question 42. Diffusivity of the liquids can be determined by

Wilke- lee equation
Wilke- chan equation
Lee and chan equation
None of the mentioned

Discuss Question

Answer: Option B. -> Wilke- chan equation
Answer: (b).Wilke- chan equation

Question 43. For the molecular diffusion of liquids, if the diffusing molecules having criteria of steady state diffusion of B over non diffusing A then the N flux of A is

1
0
Negative
Infinity

Discuss Question

Answer: Option B. -> 0
Answer: (b).0

Question 44. Find the change in concentration for a steady state equimolar counter diffusion if D(AB)= 6 sq.m/sec, the change in distance is 2 m and the N flux of A is 5 mol/sq.m sec.

0.67
1.67
2.67
None of the mentioned

Discuss Question

Answer: Option B. -> 1.67
Answer: (b).1.67

Question 45. For liquid molecular diffusion of A and B, steady state equimolar counter diffusion the N flux of A is negative of N flux of B.

True
False
May be True or False
Can't say

Discuss Question

Answer: Option A. -> True
Answer: (a).True

Question 46. Find the diffusivity of AB in sq.m/sec if N flux of A 5 mol/sq.m sec, concentration difference is 2mol/cu.m and distance is 3 m.

2.5
5.5
7.5
10.5

Discuss Question

Answer: Option C. -> 7.5
Answer: (c).7.5

Question 47. Two large vessels containing gaseous mixture of A and B at different concentrations but at the same total pressure are connected by a tapered tube of length 15cm and end diameters 1cm and 4 cm. At which point of the following locations in the tapered tube, the magnitude of the flux maximum?

At the larger diameter end
At the smaller diameter end
Midway in the tube
Somewhere in between the midway and the larger diameter end

Discuss Question

Answer: Option B. -> At the smaller diameter end
Answer: (b).At the smaller diameter end

Question 48. Two large vessels containing gaseous mixture of A and B at different concentrations but at the same total pressure are connected by a tapered tube of length 15cm and end diameters 1cm and 4 cm. what should be the diameter of a cylindrical tube of the same length that allows the same rate of transport of A?

2.5 cm
2 cm
3cm
3.5 cm

Discuss Question

Answer: Option B. -> 2 cm
Answer: (b).2 cm

Question 49. Equimolar counterdiffusion of A and B occurs through a spherical film of i.d=rᵢ and thickness δ. The flux of A is Nᴀ₁ at r=rᵢ. The flux through a flat film of the same thickness is Nᴀ₂. if Nᴀ₁ is larger than Nᴀ₂ by 5%, the film thickness δ is

0.025rᵢ
0.05rᵢ
0.1rᵢ
0.01rᵢ

Discuss Question

Answer: Option B. -> 0.05rᵢ
Answer: (b).0.05rᵢ

Question 50. Sublimation of a long cylinder made of napthelene occurs in a large volume of stagnant air. The time required for its complete sublimation is

infinite
half the time of sublimation of a sphere of the same mass
twice the time of sublimation of a cylinder of the same mass and lengthy/diameter=1
half the time of sublimation of a cylinder of the same mass and lengthy/diameter=1

Discuss Question

Answer: Option A. -> infinite
Answer: (a).infinite