1. Only small equipments are required for co-current process.
a) True
b) False
Explanation: Only for the counter current process, the mean driving force is large so small equipment is needed.
2. The driving force line between the operating line and the equilibrium line depends on
a) Relative diffusion resistance
b) Relative mass resistance
c) Cumulative resistance
d) None of the mentioned
Explanation: As the driving force changes continuously at every point in a counter current process, the relative diffusion resistance is taken into consideration.
3. Removal of ammonia from the air with water is an example of a counter-current process.
a) True
b) False
Explanation: Here, the ammonia + air is sent through one side and water is sent through other end.
4. For Air-Water system Lewis Number equals to
a) Approx 1
b) 0
c) Infinity
d) 0 to 1
Explanation: For the air-water system the simultaneous heat and mass transfer takes place. Therefore the Schmidt number (Sc) and Prandtl number (Pr) become equal. Lewis number= (Sc/Pr) equals to 1.
5. A device where two insoluble phases are brought into contact is known as
a) Trays
b) Stage
c) Cascade
d) Sieves
Explanation: The stage is a single device where the phases are allowed to contact each other.
6. Ideal stages are also known as
a) Equilibrium or Theoretical stages
b) Equilibrium or Actual stages
c) Differential or Theoretical stages
d) Differential or Actual stages
Explanation: Ideal stages are always equilibrium stages. Actual stages are practical stages hence theoretical stages are Ideal stages.
7. More than one stages are interconnected to form
a) Trays
b) Sieves
c) Cascades
d) Multiple stage
Explanation: More than one stage is cascades.
8. The main purpose of cascades is
a) To get maximum conversion
b) To increase mass transfer rates
c) To get more efficiency
d) None of the mentioned
Explanation: Though all the above mention is applicable, the main purpose is to increase the extent of mass transfer.
9. Murphree efficiency is defined as the number of equilibrium stages to the number of real stages.
a) True
b) False
Explanation: Fractional overall efficiency gives the ratio of equilibrium stage to real stage.
10. ______________ is defined as the number of equilibrium stages to the number of real stages.
a) Murphree stage efficiency
b) Fractional overall efficiency
c) Stage efficiency
d) Overall efficiency
Explanation: Fractional overall efficiency gives the ratio of equilibrium stage to real stage.