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

In which of the following unit operations, the selectivity is an important

parameter?

(A) Distillation

(B) Solvent extraction

(C) Absorption

(D) None of these

by

1 Answer

Answer :

(B) Solvent extraction

by

Related questions

Which of the following unit operations makes use of Thiele-Geddes equation? (A) Liquid-liquid extraction (B) Solid-liquid extraction (C) Multi-component absorption with chemical reaction (D) Multi-component distillation

Description : Which of the following unit operations makes use of Thiele-Geddes equation? (A) Liquid-liquid extraction (B) Solid-liquid extraction (C) Multi-component absorption with chemical reaction (D) Multi-component distillation

Last Answer : (D) Multi-component distillation

Acetic acid will be most economically separated from a dilute solution of acetic acid in water by (A) Solvent extraction (B) Continuous distillation (C) Evaporation (D) Absorption

Description : Acetic acid will be most economically separated from a dilute solution of acetic acid in water by (A) Solvent extraction (B) Continuous distillation (C) Evaporation (D) Absorption

Last Answer : (A) Solvent extraction

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)

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

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

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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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

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Last Answer : (B) No separation will occur

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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For which of the following unit operations, Lewis number is ofsignificance?(A) Adsorption(B) Binary distillation(C) Gas absorption(D) Humidification

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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

A binary mixture of benzene and cyclohexane is separated by (A) Flash vaporisation (B) Extractive distillation (C) Solvent extraction (D) Ordinary distillation

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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

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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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Last Answer : (D) Leaching

Heat sensitive materials with very high latent heat of vaporisation may be economically separated using (A) Liquid extraction (B) Distillation (C) Evaporation (D) Absorption

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Last Answer : (A) Liquid extraction

Steady state equimolal counter diffusion occurs in case of (A) Leaching (B) Absorption (C) Binary phase distillation (D) Liquid-liquid extraction

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The recovery of penicillin from the acidified fermentation broth is done by (A) Distillation (B) Evaporation (C) Absorption (D) Liquid extraction

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Polar organic compounds are normally used as separating agents for the azeotropic and extractive distillation. Which of the following is the most important factor to be considered for the choice of the separating agent for extractive distillation? (A) Cost (B) Availability(C) Toxicity(D) Selectivity

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Last Answer : (D) Selectivity

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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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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The most important application of distribution law is in (A) Evaporation (B) Liquid extraction (C) Drying (D) Distillation

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A 'unit process' is exemplified by the (A) Distillation (B) Hydrogenation of oils (C) Absorption (D) Humidification

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The reciprocal of stripping factor is termed as (A) Selectivity index (B) Relative volatility (C) Absorption factor (D) Murphree efficiency

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The expression, y(1 - x)/x(1 - y) is for (A) Absorption factor (B) Relative volatility (C) Selectivity (D) Murphree efficiency

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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 (A), (B) and (C)

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

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__________ treatment is done for appreciable improvement in viscosity index of lubricating oil. (A) Acid (B) Solvent extraction (C) Alkali (D) Clay

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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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Last Answer : (D) All 'a', 'b' & 'c'

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

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Pick out the wrong statement. (A) The operating line always lies above the equilibrium solubility curve in case of a single component absorber (B) The operating line always lies below the equilibrium solubility curve in case of a single component stripper (C) The operating pressure in solvent extraction system should be below vapor pressures of all components (D) The solubility of a particular gas in ideal solution in any solvent is always the same

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Degree of freedom for leaching and solvent extraction process is (A) 0 (B) 1 (C) 2 (D) 3

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Last Answer : (D) 3

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

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Perforated plate towers are unique for solvent extraction because, they provide (A) Higher contact area (B) Better contact of the phase (C) Repeated coalescence & redispersion of the drop phase (D) None of these

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Last Answer : (C) Repeated coalescence & redispersion of the drop phase

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

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Last Answer : (D) Carbon dioxide

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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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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Last Answer : (D) Neither (A) nor (B)

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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