For a binary mixture with low relative volatility, continuous rectification to get pure products will require (A) Low reflux ratio (B) Less number of trays (C) Small cross-section column (D) High reflux ratio

For a binary mixture with low relative volatility, continuous
rectification to get pure products will require
(A) Low reflux ratio
(B) Less number of trays
(C) Small cross-section column
(D) High reflux ratio
by

1 Answer

Answer :

(D) High reflux ratio
by

Related questions

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

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Last Answer : (C) 12

For a binary mixture with low relative volatility, (A) Use steam distillation (B) Use molecular distillation (C) Use high pressure distillation (D) An azeotrope may be formed during distillation

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Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for (A) Constant molal overflow (B) Total reflux (C) Constant relative volatility (D) All (A), (B) and (C)

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Relative volatility varies with the concentration of component for an ideal solution. The relative volatility of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when (A) Only vapor phase follows Raoult's law (B) Only liquid phase obeys Dalton's law (C) Liquid phase obeys Dalton's law and vapor phase obeys Raoult's law (D) Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law

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Minimum reflux ratio in a distillation column results in (A) Optimum number of trays (B) Minimum reboiler size (C) Maximum condenser size (D) Minimum number of trays

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Fenske equation for determining the minimum number of theoretical stages in distillation column holds good, when the (A) Relative volatility is reasonably constant (B) Mixture (to be separated) shows negative deviation from ideality (C) Mixture (to be separated) shows positive deviation from ideality (D) Multi-component distillation is involved

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Pick out the wrong statement. (A) The mole fraction of solute is directly proportional to the molality of a 'dilute' solution (B) For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is nonlinear in the case of steady state unimolal unidirectional diffusion (C) Azeotropes obey Raoult's law at all temperature (D) The relative volatility of a binary mixture at the Azeotropic composition is 1

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The-relative volatility for separation of a non-ideal binary mixture by distillation should be (A) 0 (B) 1 (C) > 1 (D) < 1

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Pick out the wrong statement. (A) Constant pressure distillation cannot separate an Azeotropic mixture (B) Relative volatility of a binary mixture changes appreciably with the minor change in temperature (C) The relative volatility of a binary mixture at Azeotropic composition is unity (D) Flash distillation is practised on wide spread scale in petroleum refinery

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The relative volatility of a binary mixture at the Azeotropic composition is (A) 1 (B) > 1 (C) 0 (D) ∞

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The relative volatility of a binary mixture at constant temperature __________ the total pressure. (A) Decreases with increase in(B) Increases with increase in(C) Is independent of(D) None of these

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The slope of 9-line is determined by the (A) Reflux ratio (B) Plate efficiency to be achieved (C) Thermal condition of the feed (D) Relative volatility

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In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of (A) Area between operating line and 45° diagonal x-y diagram (B) Condenser and reboiler surfaces (C) Tower cross-section (D) None of these

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Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio (above the minimum reflux ratio), the fixed cost of the distillation column first increases and then decreases (C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

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When the liquid phase and vapour phase of a binary system obeys Raoult's and Dalton's law respectively, the relative volatility is the ratio of (A) Vapour pressure of component A to that of component B (B) Vapour pressure of component A to the total pressure (C) Vapour pressure of component A to the partial pressure of A (D) Partial pressure of component A to the total pressure

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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

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When a multistage tray tower uses a minimum reflux ratio, it implies (A) Infinite trays and maximum reboiler heat load (B) Infinite trays and minimum reboiler heat load (C) Minimum trays and minimum reboiler heat load (D) Minimum trays and maximum reboiler heat load

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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

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With increase in pressure, the relative volatility for a binary system (A) Increases (B) Decreases (C) Remains same

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In a binary system, separation is very efficient, when the relative volatility is (A) 1 (B) > 1 (C) < 1 (D) 0.5

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As the reflux ratio in a distillation column is increased from the minimum, the (A) Slope of the operating line in stripping section decreases (B) Number of plates decreases very slowly first and then more and more rapidly (C) Total cost first decreases and then increases (D) Liquid flow increases while the vapor flow decreases for a system

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In case of __________ distillation, a solvent is added to alter the relative volatility of the mixture to be separated. (A) Molecular (B) Azeotropic (C) Extractive

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Fugacity is a measure of the (A) Escaping tendencies of the same substance in different phases of a system (B) Relative volatility of a mixture of two miscible liquids (C) Behaviour of ideal gases (D) None of these

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In stripping section of continuous distillation column, the (A) Liquid is stripped of high boiler (B) Liquid is enriched with high boiler (C) Vapour is stripped of low boiler (D) None of these

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Pick out the correct statement. (A) Higher hold up of the solid in the rotary dryer results in better exposure of the solids to the gas (B) The 'Hatta number' is important in problems involving gas absorption without chemical reaction (C) For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is linear in the case of steady state equimolal counter-diffusion (D) Total reflux in case of distillation operation requires infinite number of plates for a binary system separation

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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

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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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Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin /yout ).For 98% recovery of acetone, the number of trays required is/are: (A) 4 (B) 8 (C) 9 (D) 10

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As the reflux ratio decreases, the (A) Separation becomes more efficient (B) Number of plates increases (C) Column diameter increases (D) None of these

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The minimum number of theoretical plates is required for achieving a given separation in distillation column with (A) No reflux (B) Total reflux (C) Zero reflux ratio (D) Minimum reflux ratio

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A column is said to be a short column, when (a) its length is very small (b) its cross-sectional area is small (c) the ratio of its length to the least radhis of gyration is less than 80 (d) the ratio of its length to the least radius of gyration is more than 80

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