In liquid extraction, if the selectivity is unity, then (A) Separation of the constituents is the most effective (B) No separation will occur (C) Amount of solvent required will be minimum (D) Solvent flow rate should be very low

In liquid extraction, if the selectivity is unity, then

(A) Separation of the constituents is the most effective

(B) No separation will occur

(C) Amount of solvent required will be minimum

(D) Solvent flow rate should be very low

by

1 Answer

Answer :

(B) No separation will occur

by

Related questions

Pick out the correct statement. (A) In case of liquid-liquid extraction, no separation is possible, if the selectivity of the solvent used is unity (B) With increase in temperature, the selectivity of the solvent used in solvent extraction decreases (C) The selectivity of solvent used in solvent extraction is unity at the plait point (D) All (A), (B) and (C)

Description : Pick out the correct statement. (A) In case of liquid-liquid extraction, no separation is possible, if the selectivity of the solvent used is unity (B) With increase in temperature, the selectivity of the solvent used ... in solvent extraction is unity at the plait point (D) All (A), (B) and (C)

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

Pick out the wrong statement. (A) Critical moisture content is not a property of the material itself (B) A sharp increase in pressure drop gives an indication of the flooding in a distillation column (C) Separation of components is not possible in liquid extraction, if selectivity is unity (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

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Last Answer : (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

The solvent used in liquid-liquid extraction should have __________ less than one. (A) Selectivity (B) Distribution co-efficient(C) Both (A) and (B)(D) Neither (A) nor (B)

Description : The solvent used in liquid-liquid extraction should have __________ less than one. (A) Selectivity (B) Distribution co-efficient (C) Both (A) and (B) (D) Neither (A) nor (B)

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Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when (A) Extracting solvent is cheaply & abundantly available (B) One of the liquid components is heat sensitive (C) Viscosity of liquid components is very high (D) One of the liquid components has very high affinity towards the solvent

Description : Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when (A) Extracting solvent is cheaply & abundantly available ... very high (D) One of the liquid components has very high affinity towards the solvent

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Selectivity of the solvent used in solvent extraction should be (A) 1 (B) > 1 (C) < 1 (D) 0

Description : Selectivity of the solvent used in solvent extraction should be (A) 1 (B) > 1 (C) < 1 (D) 0

Last Answer : (B) > 1

In which of the following unit operations, the selectivity is an important parameter? (A) Distillation (B) Solvent extraction (C) Absorption (D) None of these

Description : In which of the following unit operations, the selectivity is an important parameter? (A) Distillation (B) Solvent extraction (C) Absorption (D) None of these

Last Answer : (B) Solvent extraction

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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Separation of the isotopes of helium for scientific investigations is done by (A) Reverse osmosis (B) Thermal diffusion (C) Leaching (D) Solvent extraction

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Last Answer : (B) Thermal diffusion

The solvent used in liquid extraction should not have high latent heat of vaporisation, because (A) The pressure drop and hence the pumping cost will be very high (B) It cannot be recovered by distillation (C) Its recovery cost by distillation may be prohibitively high (D) It will decompose while recovering by distillation

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Last Answer : (C) Its recovery cost by distillation may be prohibitively high

Pick out the correct statement. (A) Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of non￾ideal binary system by distillation (B) A sharp decrease in pressure drop is an indication of flooding in a distillation coloumn (C) Solvent used in extractive distillation should be of high volatility (D) Flash distillation is suitable for separating components which have very close boiling temperature

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The rate of solid-liquid extraction is limited by the (A) Phase change of the solute as it dissolves in the solvent (B) Diffusion of the solute through the solvent in the pores to the outside of the particle (C) Diffusion of the solute from the solution in contact with the particle to the main bulk of the solution (D) All 'a', 'b' & 'c'

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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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Solvent used in duo-sol extraction for lube oil upgradation is a mixture of (A) Propane & phenol-cresol mixture(B) Methyl ethyl ketone & glycol(C) Phenol & furfural(D) Propane & liquid sulphur dioxide

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Last Answer : (A) Propane & phenol-cresol mixture

When the solvent dissolves very little of solute, then (A) Solvent of low latent heat of vaporisation should be used (B) Solvent of low freezing point should be used (C) Large quantity of solvent is required to extract the solute (D) Very small quantity of solvent is required

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Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given ‘L/V’ ratio (B) The extraction per unit of total height for a short packed column is more effective than for a tall column, in case of liquid-liquid extraction(C) Natural draft cooling towers are made of ferroconcrete and its cross￾section is wider at the bottom(D) Vander wall adsorption is also called chemisorption

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Separation of two or more components of a liquid solution cannot beachieved by (A) Fractional crystallisation (B) Liquid extraction (C) Absorption (D) Evaporation

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_________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals. (A) Separation efficiency (B) Selectivity index (C) Concentration ratio (D) None of these

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Separation of two volatile liquids by distillation makes use of their (A) Selectivity (B) Relative volatility (C) Solubility (D) Density difference

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Oil produced by solvent extraction (A) Has low free fatty acid content (B) Is odourless (C) Both (A) & (B) (D) Neither (A) nor (B)

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Pick out the wrong statement pertaining to solvent extraction of oil. Rate of extraction (A) Decreases with decrease of thickness of the flakes(B) Increases with the increasing flake size keeping the flake thicknessconstant(C) Increases considerably with the rise of temperature(D) Decreases as the moisture content of flakes increases

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Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these

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Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In small columns, local efficiency is larger than Murphree efficiency; in large columns local efficiency is smaller than Murphree efficiency (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s (D) The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

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Catalyst carriers (A) Have very high selectivity (B) Increase the activity of a catalyst (C) Provide large surface area with a small amount of active material (D) Inhibit catalyst poisoning

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Pick out the wrong statement. (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity(B) For an ideal mixed reactor at steady state, the exit stream has the samecomposition as fluid within the reactor and the space time is equivalent toholding time for constant density system(C) Plug flow reactor (PFR) is always smaller than mixed reactor for allpositive reaction orders for a particular duty(D) Reaction rate does not decrease appreciably as the reaction proceeds incase of an autocatalytic reaction

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Flash distillation is suitable for separating the constituents of a binary system, which (A) Form minimum boiling azeotrope (B) Have very wide boiling points (C) Have very close boiling points (D) Form constant boiling azeotrope

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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 a single stage extraction process, 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction xf = 0.2. The mixture splits into an extract phase E and a raffinate phase R containing A at xB = 0.5 and xR = 0.05 respectively. The total mass of the extract phase is (in Kg) (A) 6.89 (B) 8.89 (C) 10 (D) 8.25

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In fluid flow, the boundary layer separation cannot occur (A) In case of boundaries experiencing form drag (B) At points of abrupt changes in the flow directions (C) In laminar flow (D) None of these

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Solvent used in the Udex (glycol) extraction process for removal of light aromatics from cracked naphtha is (A) Propane (B) Diethylene glycol (C) Aqueous solution (10% water) of diethylene glycol (D) Methyl ethyl ketone (MEK)

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Furfural solvent extraction is used for upgrading (by dissolving aromatics) (A) Naphtha (B) Lubricating oils (C) Wax (D) Cracking feedstock

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The commonly used solvent in supercritical extraction is (A) Methyl ethyl ketone (B) Water (C) Carbon tetrachloride (D) Carbon dioxide

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Essential oils are usually obtained using (A) Steam distillation (B) Extractive distillation (C) Solvent extraction (D) Leaching

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