What are Three Types of Convection - Mass Transfer Questions - Set 21 - ObjectiveBooks

What are Three Types of Convection - Mass Transfer Questions - Set 21

Practice Test: Question Set - 21

1. Bollman extractor
    (A) Is a static bed leaching equipment
    (B) Is used for extraction of oil from oilseed
    (C) Is a centrifugal extractor
    (D) Employs only counter-current extraction

2. In case of absorption, both the operating and equilibrium lines will be straight for
    (A) Isothermal operation
    (B) Dilute solutions
    (C) Dilute solutions and isothermal operation
    (D) None of these

3. The most economical range of absorption factor is
    (A) 0 to 0.5
    (B) 0 to 3
    (C) 1.25 to 2
    (D) 5 to 15

4. In a distillation operation, what is the effect of the temperature of the reflux stream (given below) on the condenser and reboiler loads?
    Reflux conditions:
    (i) Reflux stream is completely liquid and is at its bubble point.
    (ii) Reflux stream is below its bubble point.
    (A) Condenser and reboiler loads are the same in both the cases
    (B) Reboiler load is the same in both the cases but condenser load is higher in case (ii)
    (C) Condenser load is the same in both the cases but reboiler load is higher in case (ii)
    (D) Both condenser and reboiler loads are higher in case (ii) as compared to case (i)

5. In the constant rate period of the rate of drying curve for batch drying,
    (A) Cracks develop on the surface of the solid
    (B) Rate of drying decreases abruptly
    (C) Surface evaporation of unbound moisture occurs
    (D) None of these

6. Back-trapping in a distillation column
    (A) Increases tray efficiency
    (B) Decreases tray efficiency
    (C) Reduces pressure drop
    (D) Is desirable, as it provides improved vapor-liquid contact

7. Rose oil is extracted from rose leaves using __________ distillation.
    (A) High pressure
    (B) Low pressure
    (C) Extractive
    (D) Steam

8. The value of NA/(NA + NB), for steady state equimolal counter diffusion of two gases 'A' and 'B' is
    (A) 1
    (C) 0.5
    (D) 2

9. Pick out the wrong statement pertaining to the rotary dryer.
    (A) Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it down through the current of hot air/gases. It extends from the wall to a distance which is about 8-12% of the inside diameter of shell
    (B) Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at any instant. The best performance for rotary drier is obtained, when the hold up is in the range of 0.05 to 0.15
    (C) Rotary dryer is suitable for drying sticky material
    (D) Recommended peripheral speed of a rotary drier is in the range of 10 to 30 meters/minute

10. Which of the following is not a unit of mass transfer co-efficient?
    (A) Moles transferred/ [(time) (area) (mole fraction)]
    (B) Moles transferred/ [(time) (area) (mass A/mass B)]
    (C) Moles transferred/ [(time) (area) (pressure)]
    (D) None of these

11. Dry bulb temperature of the gas is __________ the wet bulb temperature.
    (A) Less than
    (B) More than
    (C) Equal to
    (D) None of these

12. __________ column is used in gas absorption process.
    (A) Wetted wall
    (B) Sieve/perforated tray
    (C) Bubble cap
    (D) Packed

13. The equilibrium liquid composition compared to the vapor composition in case of Azeotropic mixture is
    (A) More
    (B) Less
    (C) Same
    (D) Either more or less; depends on the system

14. The diffusion co-efficient in m2/s. of acetic acid in benzene (liquid in liquid) is
    (A) 2.09 × 10-4
    (B) 2.09 × 10-5
    (C) 2.09 × 10-9
    (D) 2.09 × 10-12

15. 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
    (A) And humidified
    (B) And dehumidified with increase in wet bulb temperature
    (C) At the same relative humidity
    (D) And dehumidified with decrease in wet bulb temperature

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