JD factor for mass transfer is a function of Reynolds number. Mass transfer by molecular diffusion from a single drop to surrounding still air is given by
A. Nsh = 2
B. Nst = 2
C. Nsc = 2
D. None of these
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The minimum liquid rate to be used in an absorber corresponds to an operating line
A. Of slope = 1
B. Of slope = 0.1
C. Tangential to the equilibrium curve
D. None of these
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Which of the following is an undesirable property for an absorbing solvent?
A. Low vapour pressure
B. Low velocity
C. Low freezing point
D. None of these
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The operating line for an absorber is curved, when plotted in terms of
A. Mole fractions
B. Mole ratios
C. Partial pressure
D. Mass fractions
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In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in
A. Reducing the axial mixing
B. Increasing the rate of extraction
C. Maintaining the concentration difference between the two phases
D. All of the above
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Penetration theory states that the mass transfer co-coefficient is equal to (where, De is diffusivity and 't' is time)
A. ( D e . t ) 2 1
B. ( t D e ) 2 1
C. ( π t 4 D e ) 2 1
D. t 4 D e
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In paper industry, paper is dried in a __________ dryer.
A. Tunnel
B. Heated cylinder
C. Conveyor
D. Festoon
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Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer.
A. Rotary
B. Vacuum
C. Tunnel
D. Tray
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As per Gilliland's equation, the diffusivity is
A. Directly proportional to 'T1.5 '
B. Inversely proportional to 'P'
C. Dependent on the molecular volume & molecular weight of components
D. All of the above
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H2 S present in naphtha reformed gas is removed by absorbing with
A. Ethanolamine
B. K2 CO3
C. HCl
D. Vacuum gas oil
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Pick out the wrong statement. Raoult's law does not apply, when the
A. Size of component molecules are not equal
B. Attractive forces between like and unlike molecules in the solution are approximately equal
C. Component molecules are nonpolar
D. Chemical combination or molecular association between unlike molecules takes place in the formation of solution
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__________ equation applies to diffusivities in liquids.
A. Gilliland
B. Hirschfelder
C. Wilke and Chang
D. None of these
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Pick out the wrong statement:
A. Absorption factor is constant, when the equilibrium and operating lines are straight
B. In case of a stripper, the equilibrium curve is always below the operating line
C. In case of an absorber, the operating line is always above the equilibrium curve
D. In the absorption of low solubility gases, the liquid film is the controlling resistance
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What is the degree of freedom of an absorption process in which only one component is transferred between phases?
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Separation of a mixture of two gases by absorption in the liquid solvent depends upon the difference in their
A. Viscosity
B. Density
C. Solubility
D. Relative volatility
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Schmidt number is given by
A. ρ D AB μ
B. Re × Pe
C. Sh × Pe
D. Pe Re
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Which of the following unit operations makes use of Thiele-Geddes equation?
A. Liquid-liquid extraction
B. Solid-liquid extraction
C. Multicomponent absorption with chemical reaction
D. Multicomponent distillation
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Solvent used in extractive distillation
A. Is of low volatility
B. Forms a low boiling azeotrope
C. Forms a high boiling azeotrope
D. Does not alter the relative volatility of the original components
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Solvent used in extractive distillation
A. Changes the relative volatility of the original components
B. Should be of high volatility
C. Should form azeotropes with the original components
D. All of the above
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__________ column is used in gas absorption process.
A. Wetted wall
B. Seive/perforated tray
C. Bubble cap
D. Packed
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