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This set of Mass Transfer Multiple Choice Questions & Answers (MCQs) focuses on Mass Transfer Set 10
Q1 | Free flowing granular materials can be best dried in a __________ drier.
- Rotary
- Cylinder
- Drum
- Freeze
Q2 | In a packed bed absorption column, the channelling will be noted by the
- Increase in flow rate
- Sharp drop in pressure drop
- Sharp rise in pressure drop
- None of these
Q3 | The ratio of Murphree plate efficiency to point efficiency is always > 1 in a __________ flow model.
- Plug
- Perfectly mixed
- Both (A) & (B)
- Neither (A) nor (B)
Q4 | Fractional solvent extraction
- Employs only one solvent
- Employs two solvents
- Results in low interfacial tension
- None of these
Q5 | At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid__________ that in dry packed tower.
- Is greater than
- Is lower than
- Is same as
- Cannot be predicted as data are insufficient
Q6 | During dehumidification of unsaturated air wet bulb temperature & partial pressure of vapor are not constant. However, during evaporative cooling process with recirculated water supply, the __________ remains constant.
- Wet bulb temperature
- Partial pressure of water vapor
- Relative humidity
- None of these
Q7 | Wet bulb and dry bulb temperatures becomes identical at __________ percent saturationcurve.
- 100
- 50
- 78
- None of these
Q8 | __________ is the separation technique used for desalination of sea water.
- Thermal diffusion
- Reverse osmosis
- Adsorption
- Absorption
Q9 | The partial pressure distribution of an ideal gas diffusing through another stagnant idealgas at steady state follows a/an __________ law.
- Exponential
- Parabolic
- Linear
- Cubic
Q10 | Out of two equilibrium curves, first one lies above the diagonal and the second lies below the diagonal in the x-y plot. It means that separation by distillation is
- Not possible in the second case unless vacuum is applied
- Not possible in the second case unless high pressure is applied
- More readily done in the second case compared to first one
- None of these
Q11 | According to Chilton-Colburn analogy for mass transfer, NSt.NSc 2/3 is equal to
- f
- f/2
- 2f
- 1/f
Q12 | Very tall packed towers are divided into series of beds to
- Reduce the overall pressure drop
- Avoid channelling
- Reduce liquid hold-up
- Avoid flooding
Q13 | If âfâ is defined as above, then which of the following applies to a feed at dew point?
- f = 1
- f < 1
- f > 1
- 0 < f < 1
Q14 | Separation of the isotopes of helium for scientific investigations is done by
- Reverse osmosis
- Thermal diffusion
- Leaching
- Solvent extraction
Q15 | Flash distillation is suitable for the separation of components
- Having very close boiling points
- Which form maximum boiling azeotrope
- Having very wide boiling points
- Which form minimum boiling azeotrope
Q16 | The McCabe ?L law states that the
- Molar heats of vaporisation of components are nearly equal
- Linear crystal growth rate depends on the degree of super-saturation
- Linear crystal growth rate does not depend on the crystal size
- Linear crystal growth rate depends on the crystal size
Q17 | When both the fluids flow concurrently in an absorber, the slope of the operating line is
- #NAME?
- #NAME?
- 1
- -1
Q18 | Steam distillation is used for separation of high boiling
- Substances from non-volatile impurities
- Volatile impurity from still higher boiling substances
- Both (A) and (B)
- Neither (A) nor (B)
Q19 | The relative saturation of a partially saturated mixture of vapour and gas can be increasedby __________ of the mixture.
- Reducing the total pressure
- Increasing the total pressure
- Reducing the temperature
- Both (B) and (C)
Q20 | Pick out the correct statement.
- 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
- A sharp decrease in pressure drop is an indication of flooding in a distillation coloumn
- Solvent used in extractive distillation should be of high volatility
- Flash distillation is suitable for separating components which have very close boiling temperature
Q21 | Pick out the wrong statement.
- Constant pressure distillation cannot separate an Azeotropic mixture
- Relative volatility of a binary mixture changes appreciably with the minor change in temperature
- The relative volatility of a binary mixture at Azeotropic composition is unity
- Flash distillation is practised on wide spread scale in petroleum refinery
Q22 | For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams
- Increases
- Decreases
- Remain unaffected
- Passes through a maximum
Q23 | __________ diffusion is used for separating the isotopes of methane.
- Thermal
- Pressure
- Concentration
- Force
Q24 | Pick out the wrong statement.
- The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one
- Sherwood number for flow in pipes can be expressed as the ratio of the concentration gradient at wall to the overall concentration difference
- According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2
- The z-component of the total mass flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz
Q25 | For a distillation column operating at minimum reflux, the
- Concentration of liquid and vapour leaving a plate will be same
- Reflux ratio will be maximum
- Number of plates required will be maximum
- None of these