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This set of Mass Transfer Multiple Choice Questions & Answers (MCQs) focuses on Mass Transfer Set 14

Q1 | The relative saturation of an unsaturated mixture of gas and vapor is independent of the
  • Nature of the vapor
  • Temperature of the mixture
  • Composition of the mixture
  • None of these
Q2 | In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
  • Area between operating line and 45° diagonal x-y diagram
  • Condenser and reboiler surfaces
  • Tower cross-section
  • None of these
Q3 | Advantage of continuous drying over batch drying is that the
  • Drying cost per unit weight of dried product is less
  • Product with more uniform moisture content is produced
  • Equipment size required is smaller
  • All 'a', 'b' & 'c'
Q4 | Which of the following assumes constant molal vaporisation and overflow?
  • McCabe-Thiele method
  • Ponchan-Savarit method
  • Enthalpy concentration method
  • Plate absorption column
Q5 | An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively. The humidity of air sample expressed as kg of water vapour/kg of dry air is:
  • 0.048
  • 0.079
  • 0.122
  • 0.152
Q6 | Which of the following binary systems is an example of a maximum boiling azeotrope?
  • Water-hydrochloric acid
  • Acetone-carbon disulphide
  • Water-ethyl alcohol
  • n-heptane-n-octane
Q7 | For an absorber, both equilibrium and operating line will be straight for
  • Concentrated solution and non-isothermal operation
  • Dilute solution and non-isothermal operation
  • Dilute solution and isothermal operation
  • Concentrated solution and isothermal operation
Q8 | Channelling is most severe
  • In towers packed with stacked packing
  • In towers packed randomly with crushed solids
  • In dumped packing of regular units
  • At very high liquid flow rate
Q9 | Penetration model (theory) for mass transfer was enunciated by
  • Danckwerts
  • Toor and Marcello
  • Higbie
  • Kissinevskii
Q10 | Pick out the correct statement.
  • Bound moisture is removed during constant rate drying period
  • Free moisture is removed during falling rate drying period
  • The sum of free moisture and equilibrium moisture in a solid is called the critical moisture
  • The driving force for mass tr
Q11 | Milk is dried usually in a __________ dryer.
  • Freeze
  • Spray
  • Tray
  • Rotary
Q12 | Extraction of coffee from its seed is done by
  • Liquid-liquid extraction
  • Leaching
  • Extractive distillation
  • Steam distillation
Q13 | Unit of molal diffusivity is
  • cm2/sec gm . mole
  • gm moles/cm2 . sec
  • gm moles/cm. sec
  • gm moles/cm2. sec
Q14 | 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
  • Vapour pressure of component A to that of component B
  • Vapour pressure of component A to the total pressure
  • Vapour pressure of component A to the partial pressure of A
  • Partial pressure of component A to the total pressure
Q15 | In case of non-ideal gases and liquids, the molal diffusivity
  • Varies inversely as the pressure
  • Varies directly as the pressure
  • Is independent of pressure
  • Is equal to the volumetric diffusivity
Q16 | Flooding in a column results due to
  • High pressure drop
  • Low pressure drop
  • Low velocity of the liquid
  • High temperature
Q17 | Which of the following is a suitable absorbent for removal of H2S from natural gas?
  • Vetrocoke solution
  • Monoethanolamine (MEA)
  • Dilute
  • Hot water
Q18 | Raoult's law is applicable to the
  • Ideal solutions
  • Real solutions
  • Mixture of water and alcohol
  • Non-ideal gases
Q19 | Humid volume is the total volume in m3 of 1 kg of
  • Vapour laden gas at 1 atm. and room temperature
  • Gas plus its accompanying vapour at 1 atm. and room temperature
  • Gas plus its accompanying vapour at 1 atm. and gas temperature
  • Vapour laden gas at 1 atm. and gas temperature
Q20 | Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer.
  • Rotary
  • Vacuum
  • Tunnel
  • Tray
Q21 | Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation.
  • Molecular
  • Extractive
  • Steam
  • Simple
Q22 | Pick out the system with minimum boiling azeotrope at 1 atm.
  • Benzene-toluene
  • Ethyl alcohol-water
  • Hydrochloric acid-water
  • All (A), (B) and (C)
Q23 | Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and
  • Humidified with wet bulb temperature decreasing
  • Humidified at constant wet bulb temperature
  • Dehumidified
  • None of these
Q24 | The film penetration model of mass transfer was enunciated by
  • Gilliland
  • Toor and Marcello
  • Stefan
  • Fick
Q25 | Equilibrium moisture of a solid is equal to the total moisture minus free moisture. Which of the following substances will have maxi-mum equilibrium moisture?
  • Anthracite coal
  • Rag paper
  • Bamboo
  • Inorganic solids