Category: Mass Transfer

For an absorber, both equilibrium and operating line will be straight for _______________________?

Hamad Mass Transfer 08/06/2021

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A. Concentrated solution and non-isothermal operation
B. Dilute solution and non-isothermal operation
C. Dilute solution and isothermal operation
D. Concentrated solution and isothermal operation

A pure drug is administered as a sphere and as a cube. The amount of drug is the same in the two tablets. Assuming that the shape and size do not influence the mass transfer, the ratio of rate of dissolution in water at t = 0 for the cubic to spherical tablet is___________________?

Hamad Mass Transfer 08/06/2021

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A. 0.54
B. 1.04
C. 1.24
D. 1.94

Fenske equation determines the __________________?

Hamad Mass Transfer 06/06/2021

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A. Maximum number of ideal plates
B. Height of the distillation column
C. Minimum number of theoretical plates
D. Optimum reflux ratio

Mass transfer co-efficient (K) and diffusivity D. are related according to film theory as______________________?

Hamad Mass Transfer 03/06/2021

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A. K ∝ D
B. K ∝√D
C. K ∝ D1.5
D. K ∝ D2

The main reason for dividing a tall packed tower into series of small towers is to________________________?

Hamad Mass Transfer 01/06/2021

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A. Minimise the overall pressure drop
B. Avoid flooding
C. Reduce liquid hold up
D. Avoid channelling

According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility (αAB = 2) does not change appreciably in the column ?

Hamad Mass Transfer 31/05/2021

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A. 5
B. 9
C. 12
D. 28

The dimension of diffusivity is same as that of the__________________?

Hamad Mass Transfer 30/05/2021

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The dimension of diffusivity is same as that of the
A. Density
B. Molal concentration
C. Kinematic viscosity
D. Velocity head

H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in meters) corresponding to an operating line given by, y = 5x + 0.001 is ______________________?

Hamad Mass Transfer 26/05/2021

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A. 2.0
B. 1.56
C. 1.0
D. 0.56

Pick out the wrong statement?

Hamad Mass Transfer 26/05/2021

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A. Mass transfer co-efficient does not account for gas-liquid diffusion
B. Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer
operation
C. Contacting cold vapor-gas mixture with hot liquid exemplifies humidification process
D. Contacting cold liquid with warm vapor-gas mixture exemplifies dehumidification process

In a packed bed absorption column, the channelling will be noted by the ____________________?

Hamad Mass Transfer 25/05/2021

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A. Increase in flow rate
B. Sharp drop in pressure drop
C. Sharp rise in pressure drop
D. None of these