Mass Transfer Mock Test 10

10%

Question 1 of 10

1. Diffusivity of the liquids can be determined by

Wilke- lee equation

None of the mentioned

Wilke- chan equation

Lee and chan equation

Question 1 of 10

Question 2 of 10

2. 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?

3cm

3.5 cm

2 cm

2.5 cm

Question 2 of 10

Question 3 of 10

3. 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.

2.5

3.5

Question 3 of 10

Question 4 of 10

4. 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 cylinder of the same mass and lengthy/diameter=1

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

Question 4 of 10

Question 5 of 10

5. 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.

2.67

0.67

None of the mentioned

1.67

Question 5 of 10

Question 6 of 10

6. 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?

D_1m=(Y₁∑N_j)/(∑(Y_jN₁-Y₁N_j)/D_ij)

D_1m=(1-Y₁)/(∑[Y_j/D_ij])

D_1m=N₁/(∑[(Y_jN₁-Y₁N_j)/D_ij])

D_1m=(N₁-Y₁∑N_j)/(∑(Y_jN₁-Y₁N_j)/D_ij)

Question 6 of 10

Question 7 of 10

7. 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

Difference in the velocities at point A and B

Velocity at the point A

The molar concentration at the two points

Length of the diffusion path

Question 7 of 10

Question 8 of 10

8. Find the diffusivity through slab if N flux of A 4 mol/sq.m sec, concentration difference is 2mol/cu.m and distance is 3 m.

8 sq.m/s

6 sq.m/s

2 sq.m/s

4 sq.m/s

Question 8 of 10

Question 9 of 10

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

N flux of A

N flux of B

– N flux of B

– N flux of A

Question 9 of 10

Question 10 of 10

10. A tapered tube of length 8cm and end diameters 2cm and 4cm connects two vessels containing mixtures of A and B. if the tapered tube is replaced with a cylindrical tube of diameter 6cm, what will be the required length of the cylindrical tube to maintain the same flow rate as in the previous case?

8cm

36cm

48cm

16cm

Question 10 of 10