To get high tray efficiency (A) Interfacial surface between liquid and gas phase should be large (B) Time of contact between the two phases should be less (C) Gas velocity should be very low (D) Liquid entrainment should be severe

To get high tray efficiency

(A) Interfacial surface between liquid and gas phase should be large

(B) Time of contact between the two phases should be less

(C) Gas velocity should be very low

(D) Liquid entrainment should be severe

by

1 Answer

Answer :

(A) Interfacial surface between liquid and gas phase should be large


by

Related questions

Weeping in a distillation column (A) Increases tray efficiency (B) Provides large interfacial surface for mass transfer (C) Results due to very high gas velocity (D) Results due to very low gas velocity

Description : Weeping in a distillation column (A) Increases tray efficiency (B) Provides large interfacial surface for mass transfer (C) Results due to very high gas velocity (D) Results due to very low gas velocity

Last Answer : (D) Results due to very low gas velocity

Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low interfacial tension (C) When Henry's law constant is very small, then the mass transfer rate is controlled by the gas film resistance (D) Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Description : Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low ... Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Last Answer : (A) Mechanical agitation is required, if the system has low interfacial tension

Flooding results in (A) High tray efficiency (B) Low tray efficiency (C) High gas velocity (D) Good contact between the fluids

Description : Flooding results in (A) High tray efficiency (B) Low tray efficiency (C) High gas velocity (D) Good contact between the fluids

Last Answer : (B) Low tray efficiency

In the Lurgi coal gasifier (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Large quantity of coal can be processed

Description : In the Lurgi coal gasifier (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Large quantity of coal can be processed

Last Answer : (D) Large quantity of coal can be processed

The rate of mass transfer is not dependent upon the (A) Degree of dispersion of one fluid in the other (B) Interfacial surface exposed between the phases (C) Both (A) & (B) (D) None of these

Description : The rate of mass transfer is not dependent upon the (A) Degree of dispersion of one fluid in the other (B) Interfacial surface exposed between the phases (C) Both (A) & (B) (D) None of these

Last Answer : (D) None of these

Back-trapping in a distillation column (A) Increases tray efficiency (B) Decreases tray efficiency (C) Reduces pressure drop (D) Is desirable, as it provides improved vapour-liquid contact

Description : Back-trapping in a distillation column (A) Increases tray efficiency (B) Decreases tray efficiency (C) Reduces pressure drop (D) Is desirable, as it provides improved vapour-liquid contact

Last Answer : (B) Decreases tray efficiency

In continuous fluidisation (A) Solids are completely entrained (B) The pressure drop is less than that for batch fluidisation (C) There is no entrainment of solids (D) Velocity of the fluid is very small

Description : In continuous fluidisation (A) Solids are completely entrained (B) The pressure drop is less than that for batch fluidisation (C) There is no entrainment of solids (D) Velocity of the fluid is very small

Last Answer : (A) Solids are completely entrained

Plate efficiency (A) Is a function of the mass transfer between liquid and vapour (B) Increases due to foaming (C) Increases due to liquid entrainment (D) Increases due to weeping and dumping of liquid

Description : Plate efficiency (A) Is a function of the mass transfer between liquid and vapour (B) Increases due to foaming (C) Increases due to liquid entrainment (D) Increases due to weeping and dumping of liquid

Last Answer : (A) Is a function of the mass transfer between liquid and vapour

Plate efficiency in a distillation column is reduced due to the __________ of liquid. (A) Entrainment (B) Foaming (C) Weeping & dumping (D) All (A), (B) & (C)

Description : Plate efficiency in a distillation column is reduced due to the __________ of liquid. (A) Entrainment (B) Foaming (C) Weeping & dumping (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of gases in solvent increases at a fixed temperature (C) Decrease in Murphree plate efficiency is an indication of entrainment in distillation column (D) The capacity of a distillation column is maximum at total reflux

Description : Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of ... in distillation column (D) The capacity of a distillation column is maximum at total reflux

Last Answer : (D) The capacity of a distillation column is maximum at total reflux

Mass transfer rate between two fluid phases does not necessarily depend on the __________ of the two phases. (A) Chemical properties (B) Physical properties (C) Degree of turbulence (D) Interfacial area

Description : Mass transfer rate between two fluid phases does not necessarily depend on the __________ of the two phases. (A) Chemical properties (B) Physical properties (C) Degree of turbulence (D) Interfacial area

Last Answer : (A) Chemical properties

In Lurgi coal gasifier, (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Larger quantity of coal can be processed

Description : In Lurgi coal gasifier, (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Larger quantity of coal can be processed

Last Answer : (D) Larger quantity of coal can be processed

Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface? (A) Liquid density (B) Liquid viscosity (C) Hot surface temperature (D) Interfacial tension

Description : Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface? (A) Liquid density (B) Liquid viscosity (C) Hot surface temperature (D) Interfacial tension

Last Answer : (D) Interfacial tension

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) nochange in the(A) Drag on particles(B) Drag on column walls(C) Bed height(D) Bed voidage

Description : Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles ... (A) Drag on particles (B) Drag on column walls (C) Bed height (D) Bed voidage

Last Answer : (C) Bed height

In distillation columns, the number of bubble caps per tray primarily depends upon the (A) Allowable liquid velocity (B) Allowable gas velocity (C) Allowable gas and liquid velocities

Description : In distillation columns, the number of bubble caps per tray primarily depends upon the (A) Allowable liquid velocity (B) Allowable gas velocity (C) Allowable gas and liquid velocities

Last Answer : (C) Allowable gas and liquid velocities

The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling? (A) Liquid side (B) Gas side (C) Interfacial (D) Both liquid and gas side

Description : The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of ... A) Liquid side (B) Gas side (C) Interfacial (D) Both liquid and gas side

Last Answer : (B) Gas side

The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2 /m3 ) (A) 500 (B) 1200 (C) 900 (D) 800

Description : The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2 /m3 ) (A) 500 (B) 1200 (C) 900 (D) 800

Last Answer : (A) 500

Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer. (A) Less than (B) More than (C) Same as (D) Very much less

Description : Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer. (A) Less than (B) More than (C) Same as (D) Very much less

Last Answer : (B) More than

Entrainer used in Azeotropic distillation should (A) Form a low boiling azeotrope with one of the constituents of the mixture (B) Form a new azeotrope of low relative volatility with one of the constituents of the mixture (C) Have high latent heat of vaporisation (D) Have high viscosity to provide high tray efficiency

Description : Entrainer used in Azeotropic distillation should (A) Form a low boiling azeotrope with one of the constituents of the mixture (B) Form a new azeotrope of low relative volatility with one of the ... (C) Have high latent heat of vaporisation (D) Have high viscosity to provide high tray efficiency

Last Answer : (A) Form a low boiling azeotrope with one of the constituents of the mixture

In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate

Description : In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate

Last Answer : (C) Foaming of the solution

One of the methods of purification of leach liquor is ion exchange, which involves (A) Exchange between two liquid phases (B) Exchange between a gaseous phase and a liquid phase (C) Exchange between a liquid phase and an organic resin phase (D) Exchange between a solid phase and a gas phase

Description : One of the methods of purification of leach liquor is ion exchange, which involves (A) Exchange between two liquid phases (B) Exchange between a gaseous phase and a liquid phase (C) Exchange between a liquid phase and an organic resin phase (D) Exchange between a solid phase and a gas phase

Last Answer : (C) Exchange between a liquid phase and an organic resin phase

In case of absorption & stripping, the interface of the liquid & gas phases are present in equilibrium, when the diffusional resistance of __________ is zero. (A) Interface (B) Gas phase (C) Liquid phase (D) All 'a', 'b' & 'c'

Description : In case of absorption & stripping, the interface of the liquid & gas phases are present in equilibrium, when the diffusional resistance of __________ is zero. (A) Interface (B) Gas phase (C) Liquid phase (D) All 'a', 'b' & 'c'

Last Answer : (A) Interface

For absorbers, high pressure drop results in (A) Increased efficiency (B) Decreased efficiency (C) High operating cost (D) Better gas liquid contact

Description : For absorbers, high pressure drop results in (A) Increased efficiency (B) Decreased efficiency (C) High operating cost (D) Better gas liquid contact

Last Answer : (C) High operating cost

The separation of liquid droplets from the vapor is done by a/an __________, in the evaporators. (A) Steam ejector (B) Entrainment separator (C) Compressor (D) Vacuum pump

Description : The separation of liquid droplets from the vapor is done by a/an __________, in the evaporators. (A) Steam ejector (B) Entrainment separator (C) Compressor (D) Vacuum pump

Last Answer : (B) Entrainment separator

Priming in a distillation column (A) Results from very low gas velocity (B) Is desirable from point efficiency consideration (C) Is characterised by the presence of foam throughout the space between trays (D) Reduces the overall pressure drop

Description : Priming in a distillation column (A) Results from very low gas velocity (B) Is desirable from point efficiency consideration (C) Is characterised by the presence of foam throughout the space between trays (D) Reduces the overall pressure drop

Last Answer : (C) Is characterised by the presence of foam throughout the space between trays

. __________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction. (A) Packed (B) Bubble (C) Spray (D) Tray

Description : . __________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction. (A) Packed (B) Bubble (C) Spray (D) Tray

Last Answer : (B) Bubble

When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ column. (A) Packed (B) Spray (C) Tray (D) Bubble

Description : When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ column. (A) Packed (B) Spray (C) Tray (D) Bubble

Last Answer : (D) Bubble

(4) Water drops in a dispersion medium of air Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Cloud is a colloidal dispersion of Water drops in a dispersion medium of air.

Description : (4) Water drops in a dispersion medium of air Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed ... or gas. Cloud is a colloidal dispersion of Water drops in a dispersion medium of air.

Last Answer : Conduction band electrons have more mobility than holes because they – (1) are lighter (2) experience collision less frequently (3) have negative charge (4) need less energy to move them

(2) Fat is dispersed in water Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.

Description : (2) Fat is dispersed in water Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed ... Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.

Last Answer : The presence of ozone in the stratosphere is responsible for – (1) increasing the average global temperature in recent years (2) higher rate of photosynthesis (3) checking the penetration of ultra-violet rays to the earth (4) supplying oxygen for people travelling in jets

(2) Fat is dispersed in water Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.

Description : (2) Fat is dispersed in water Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed ... Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.

Last Answer : The presence of ozone in the stratosphere is responsible for – (1) increasing the average global temperature in recent years (2) higher rate of photosynthesis (3) checking the penetration of ultra-violet rays to the earth (4) supplying oxygen for people travelling in jets

In extractive distillation, solvent is (A) Added to alter the relative volatility of the mixture (B) Of high volatility (C) Present in overhead stream (D) Of high viscosity to give high tray efficiency

Description : In extractive distillation, solvent is (A) Added to alter the relative volatility of the mixture (B) Of high volatility (C) Present in overhead stream (D) Of high viscosity to give high tray efficiency

Last Answer : (A) Added to alter the relative volatility of the mixture

Fractional solvent extraction (A) Employs only one solvent (B) Employs two solvents (C) Results in low interfacial tension (D) None of these

Description : Fractional solvent extraction (A) Employs only one solvent (B) Employs two solvents (C) Results in low interfacial tension (D) None of these

Last Answer : (B) Employs two solvents

A batch reactor is (A) Suitable for gas-phase reactions on commercial scale (B) Suitable for liquid phase reactions involving small production rate (C) Least expensive to operate for a given rate (D) Most suitable for very large production rate

Description : A batch reactor is (A) Suitable for gas-phase reactions on commercial scale (B) Suitable for liquid phase reactions involving small production rate (C) Least expensive to operate for a given rate (D) Most suitable for very large production rate

Last Answer : (B) Suitable for liquid phase reactions involving small production rate

Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. (A) Wetted wall (B) Bubble cap (C) Perforated tray (D) Packed

Description : Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. (A) Wetted wall (B) Bubble cap (C) Perforated tray (D) Packed

Last Answer : (A) Wetted wall

Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty? (A) Grid tray tower (B) Perforated tray tower (C) Wetted wall tower (D) Bubble cap tower

Description : Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty? (A) Grid tray tower (B) Perforated tray tower (C) Wetted wall tower (D) Bubble cap tower

Last Answer : (D) Bubble cap tower

In sub-cooled boiling, (A) Temperature of the heating surface is less than the boiling point of the liquid (B) Temperature of the heating surface is more than the boiling point of the liquid (C) Bubbles from heating surface are absorbed by the mass of the liquid (D) Very large vapour space is necessary

Description : In sub-cooled boiling, (A) Temperature of the heating surface is less than the boiling point of the liquid (B) Temperature of the heating surface is more than the boiling point of the liquid (C) ... from heating surface are absorbed by the mass of the liquid (D) Very large vapour space is necessary

Last Answer : (B) Temperature of the heating surface is more than the boiling point of the liquid

The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are: (A) 1 (B) 2 (C) 3 (D) 0

Description : The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are: (A) 1 (B) 2 (C) 3 (D) 0

Last Answer : (B) 2

When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is (A) Same in both the phases (B) Zero in both the phases (C) More in vapour phase (D) More in liquid phase

Description : When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is (A) Same in both the phases (B) Zero in both the phases (C) More in vapour phase (D) More in liquid phase

Last Answer : (A) Same in both the phases

When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is (A) More in vapour phase (B) More in liquid phase (C) Same in both the phases (D) Replaced by chemical potential which is more in vapour phase

Description : When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is (A) More in vapour phase (B) More in liquid phase (C) Same in both the phases (D) Replaced by chemical potential which is more in vapour phase

Last Answer : (C) Same in both the phases

If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent(A) 100(B) > 100(C) < 100(D) None of these

Description : If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent (A) 100 (B) > 100 (C) < 100 (D) None of these

Last Answer : (B) > 100

At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.) (A) μ° + RT ln f (B) μ°+ R ln f (C) μ° + T ln f (D) μ° + R/T ln f

Description : At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm. ... (B) μ°+ R ln f (C) μ° + T ln f (D) μ° + R/T ln f

Last Answer : (A) μ° + RT ln f

Pick out the wrong statement. (A) Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point (B) Entropy of a system decreases with the evolution of heat (C) Change of internal energy is negative for exothermic reactions (D) The eccentric factor for all materials is always more than one

Description : Pick out the wrong statement. (A) Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point (B) Entropy of ... is negative for exothermic reactions (D) The eccentric factor for all materials is always more than one

Last Answer : (D) The eccentric factor for all materials is always more than one

At the critical point of a substance (A) The surface tension vanishes (B) Liquid and vapour have the same density (C) There is no distinction between liquid and vapour phases (D) All (A), (B) and (C)

Description : At the critical point of a substance (A) The surface tension vanishes (B) Liquid and vapour have the same density (C) There is no distinction between liquid and vapour phases (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Multistage operation (as in the case of catalytic oxidation of SO2 ) is not carried out for NH3 synthesis, because of (A) Comparatively higher pressure drop (B) High cost of the high pressure vessel used for the reactor (C) Higher pumping cost (D) Chances of entrainment and disturbance of catalyst bed

Description : Multistage operation (as in the case of catalytic oxidation of SO2 ) is not carried out for NH3 synthesis, because of (A) Comparatively higher pressure drop (B) High cost of the high pressure ... for the reactor (C) Higher pumping cost (D) Chances of entrainment and disturbance of catalyst bed

Last Answer : (B) High cost of the high pressure vessel used for the reactor

Urea is formed only (A) In liquid phase (B) In vapour phase (C) At very high temperature (D) At very low pressure (vacuum)

Description : Urea is formed only (A) In liquid phase (B) In vapour phase (C) At very high temperature (D) At very low pressure (vacuum)

Last Answer : (A) In liquid phase

Stage efficiency in a leaching process depends on the (A) Time of contact between the solid and the solution (B) Rate of diffusion of the solute through the solid and into the liquid (C) Both (A) and (B) (D) Vapour pressure of the solution

Description : Stage efficiency in a leaching process depends on the (A) Time of contact between the solid and the solution (B) Rate of diffusion of the solute through the solid and into the liquid (C) Both (A) and (B) (D) Vapour pressure of the solution

Last Answer : (C) Both (A) and (B)

Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)

Description : Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

A trickle bed reactor is the one, which (A) Has altogether three streams either entering or leaving (B) Processes three reactants at different flow rates (C) Processes three reactants with same flow rate (D) Employs all the three phases (i.e. solid, liquid and gas)

Description : A trickle bed reactor is the one, which (A) Has altogether three streams either entering or leaving (B) Processes three reactants at different flow rates (C) Processes three reactants with same flow rate (D) Employs all the three phases (i.e. solid, liquid and gas)

Last Answer : (D) Employs all the three phases (i.e. solid, liquid and gas)

The temperature at which both liquid and gas phases are identical, is called the __________ point. (A) Critical (B) Triple (C) Freezing (D) Boiling

Description : The temperature at which both liquid and gas phases are identical, is called the __________ point. (A) Critical (B) Triple (C) Freezing (D) Boiling

Last Answer : (A) Critical