On This Page
This set of Mass Transfer Multiple Choice Questions & Answers (MCQs) focuses on Mass Transfer Set 13
Q1 | Dry bulb temperature of the gas is __________ the wet bulb temperature.
- Less than
- More than
- Equal to
- None of these
Q2 | __________ column is used in gas absorption process.
- Wetted wall
- Sieve/perforated tray
- Bubble cap
- Packed
Q3 | The equilibrium liquid composition compared to the vapor composition in case of Azeotropic mixture is
- More
- Less
- Same
- Either more or less; depends on the system
Q4 | The diffusion co-efficient in m2/s. of acetic acid in benzene (liquid in liquid) is
- 2.09 × 10-4
- 2.09 × 10-5
- 2.09 × 10-9
- 2.09 × 10-12
Q5 | Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled
- And humidified
- And dehumidified with increase in wet bulb temperature
- At the same relative humidity
- And dehumidified with decrease in wet bulb temperature
Q6 | The 'shanks system' of leaching (i.e., counter-current multiple contact leaching) is used for
- Recovery of tannis from the tree barks and woods
- Leaching sodium nitrate from Chilean nitrate bearing rock
- Both (A) and (B)
- Neither (A) nor (B)
Q7 | The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around
- 1
- 0.24
- 3.97
- 600
Q8 | Which of the following employs an accessory known as 'drift eliminator'?
- Multiple effect evaporator
- Mechanical draft cooling tower
- Rotary dryer
- Rotating disc contactor
Q9 | Dew point of an air-water vapor mixture
- Decreases with decrease in pressure
- At constant humidity & total pressure is fixed
- Corresponding to any point on the humidity chart is obtained by projecting a line through this point parallel to the temperature axis and to the saturation curve
- All 'a', 'b' & 'c'
Q10 | The term "approach" in a cooling tower refers to the difference in the temperature of the
- Cold water leaving the tower and the wet bulb temperature of the surrounding air
- Hot water entering the tower and the wet bulb temperature of the surrounding air
- Hot water entering and the cooled water leaving the cooling tower
- None of these
Q11 | The relation, Sc = Pr = 1, is valid, when the mechanism of __________ transfer is same.
- Heat and mass
- Mass and momentum
- Heat and momentum
- Heat, momentum and mass
Q12 | McCabe-Thiele method
- Uses molal units for material and energy balance
- Uses weight fractions to express liquid and vapour composition
- Can use any type of units
- Is more accurate than Ponchon-Savarit method
Q13 | If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent.
- 100
- > 100
- < 100
- None of these
Q14 | Humid volume, at a given temperature is a/an __________ function of humidity.
- Inverse
- Exponential
- Linear
- Logarithmic
Q15 | If the specific heats of a gas and a vapor are 0.2KJ/Kg.°K and 1.5 KJ/Kg.°K respectively, and the humidity is 0.01; the humid heat in KJ/°Kg. is
- 0.31
- 0.107
- 0.017
- 0.215
Q16 | Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.
- Less than
- More than
- Same as
- Very much less
Q17 | In case of __________ distillation, a solvent is added to alter the relative volatility of themixture to be separated.
- Molecular
- Azeotropic
- Extractive
- Flash
Q18 | Pick out the wrong statement.
- Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse
- Packed towers are preferred over plate towers for handling corrosive and foamy liquids
- Diameter of randomly packed tower is normally more than 1.2 metres
- Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers
Q19 | Moisture contained by a substance in excess of the equilibrium moisture is called the __________ moisture.
- Unbound
- Free
- Critical
- Bound
Q20 | Which of the following is an undesirable characteristic for the solvent used in gas absorption?
- Low vapor pressure
- Low viscosity
- High gas solubility
- None of these
Q21 | Hypersorption refers to a __________ process.
- Fixed bed absorption
- Moving bed absorption
- Fixed bed adsorption
- Moving bed adsorption
Q22 | Drying of refractory is normally carried out in a __________ dryer.
- Open pan
- Tray
- Rotary vacuum
- Truck/tunnel
Q23 | For the same feed, feed quality and separation (in a distillation column), with the increaseof total pressure, the number of ideal plates will
- Increase
- Decrease
- Remain same
- Data insufficient, can't be predicted
Q24 | In case of liquids, the binary diffusivity is proportional to (where, T = temperature)
- T
- ?T
- T 2
- 1/T
Q25 | A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?
- The mixture exhibits an azeotrope at 101.3 kPa
- The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m- xylene 10
- The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10
- The mixture contain optical isomers