441. To remove all the moisture from a wet solid it requires exposure to __________ air.
Perfectly dry
Highly humid
High temperature
None of these
✅ The correct answer is option A.
Mass Transfer MCQs
442. Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 x 10⁻³ kg mole/m².s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m² .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is
5.6 x 10⁻⁴
8.5 x 10⁻⁴
5.6 x 10⁻³
8.5 x 10⁻³
✅ The correct answer is option B.
443. Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when
Extracting solvent is cheaply & abundantly available
One of the liquid components is heat sensitive
Viscosity of liquid components is very high
One of the liquid components has very high affinity towards the solvent
✅ The correct answer is option D.
444. In case of __________ distillation, a solvent is added to alter the relative volatility of the mixture to be separated.
Molecular
Azeotropic
Extractive
Flash
✅ The correct answer is option C.
445. ‘ADDUCTS’ and ‘CLATHRATES’ are used in case of
Extractive distillation
Crystallisation
Absorption
None of these
✅ The correct answer is option B.
446. During constant rate drying period, vaporisation rate per unit drying surface area
Decreases with time
Increases with time
Does not change with time
Does not affect the moisture content of the wet solid
✅ The correct answer is option C.
447. Which of the following is a suitable absorbent for removal of H₂S from natural gas?
Vetrocoke solution
Monoethanol amine (MEA)
Dilute
Hot water
✅ The correct answer is option B.
448. Mass transfer co-efficient varies as DAB0.5, according to the __________ theory.
Film
Surface renewal
Penetration
None of these
✅ The correct answer is option B.
449. Which of the following operations does not involve leaching?
Dissolving gold from ores
Dissolving pharmaceutical products from bark or roots
Dissolving sugar from the cells of the beet
Removing nicotine from its water solution by kerosene
✅ The correct answer is option D.
450. The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will
Increase
Decrease
Remains same
Depend on saturated boiling point; may increase or decrease
✅ The correct answer is option A.