The driving potential for the crystal growth during crystallisation is the _______________ of the solution?

Related Mcqs:

1. During crystallisation, formation of crystal can occur in ______________ solution only?

   A. Saturated
   B. Supersaturated
   C. Under-saturated
   D. All A., B. and C.

2. It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is____________________?

   A. 3.06 × 105
   B. 6.12 × 105
   C. 7.24 × 105
   D. 9.08 × 105

3. In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________?

   A. More
   B. Less
   C. Same
   D. More or less; depends on the nature of solution

4. Crystallisation of solids from a homogeneous solution is a/an ______________ process?

   A. Exothermic
   B. Mildly endothermic
   C. Highly endothermic
   D. None of these

5. Boiling point elevation for a strong and concentrated solution is found by Duhring’s rule, which states that at the same pressure, the boiling point of a solution is a linear function of the _______________ of pure water?

   A. Boiling point
   B. Dynamic viscosity
   C. Kinematic viscosity
   D. Density

6. For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a _______________ evaporator?

   A. High pressure
   B. Vacuum
   C. Backward feed
   D. None of these

7. Crystal size in a continuous crystalliser depends upon the___________________?

   A. Rate of heat transfer
   B. Degree of turbulence
   C. Degree of super-saturation
   D. All A., B. and C

8. Open pan evaporators are preferred to be used, when the solution to be concentrated is_________________?

   A. Scaling
   B. Highly viscous
   C. Corrosive
   D. Salty

9. Evaporation of 1kg of water from a solution in a single effect evaporator requires about ________________ kg of steam?

   A. 0.4 – 0.6
   B. 1-1.3
   C. 1.8-2
   D. 2 – 2.4

10. For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is _________________?

    A. Forward
    B. Backward
    C. Parallel
    D. None of these