Mass Transfer Set 26

Mechanical Engineering

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This set of Mass Transfer Multiple Choice Questions & Answers (MCQs) focuses on Mass Transfer Set 26

Q1 | With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature).
  • Increases
  • Remains unchanged
  • Decreases
  • Decreases linearly
Answer: Increases
Q2 | As the reflux ratio decreases, the
  • Separation becomes more efficient
  • Number of plates increases
  • Column diameter increases
  • None of these
Answer: Number of plates increases
Q3 | Only small amount of evaporation of water produces large cooling effects because of its
  • Large latent heat
  • Low viscosity
  • Small latent heat
  • None of these
Answer: Large latent heat
Q4 | Ion exchange process is similar to
  • Absorption
  • Adsorption
  • Extraction
  • Leaching
Answer: Adsorption
Q5 | Physical absorption is
  • An irreversible phenomenon
  • A reversible phenomenon
  • Accompanied by evolution of heat
  • Both (B) and (C)
Answer: Both (B) and (C)
Q6 | Corresponding to Prandtl number in heat transfer, the dimensionless group in mass transfer is the __________ number.
  • Schmidt
  • Sherwood
  • Peclet
  • Stanton
Answer: Schmidt
Q7 | If G = insoluble gas in gas stream and L = non-volatile solvent in liquid stream, then the slope of the operating line for the absorber is
  • L/G
  • G/L
  • Always < 1
  • None of these
Answer: L/G
Q8 | For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of __________ microns (1 mm = 1000 microns).
  • 05-Jan
  • 10-60
  • 200-300
  • > 500
Answer: 10-60
Q9 | Berl saddle made of carbon cannot be used for
  • Alkalis
  • SO2
  • H2SO4
  • Oxidising atmosphere
Answer: Oxidising atmosphere
Q10 | Capacity of a rotary dryer depends on its
  • rpm
  • Inclination with ground surface
  • Both (A) and (B)
  • Neither (A) nor (B)
Answer: Both (A) and (B)
Q11 | The most common packing used in industrial operations is __________ rings.
  • Raschig
  • Lessing
  • Cross-partition
  • Single spiral
Answer: Raschig
Q12 | Refractory bricks are usually dried in a __________ dryer.
  • Tray
  • Tunnel
  • Conveyor
  • Festoon
Answer: Tunnel
Q13 | Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate.
  • Increases
  • Decreases
  • Does not affect
  • Exponentially increases
Answer: Decreases
Q14 | The binary diffusivity in gases at atmospheric conditions is about
  • 10-9 cm/sec
  • 10-1 cm2/sec
  • 10-3 sec/cm
  • 10-4 cm2/sec2
Answer: 10-1 cm2/sec
Q15 | For absorbers, high pressure drop results in
  • Increased efficiency
  • Decreased efficiency
  • High operating cost
  • Better gas liquid contact
Answer: High operating cost
Q16 | __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid.
  • Dew point
  • Bubble point
  • Dry bulb temperature
  • Wet bulb temperature
Answer: Dew point
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