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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