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

Related Mcqs:

1. 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

2. 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

3. An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is___________________?

   A. 4000
   B. 9000
   C. 4600
   D. 3000

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

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

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

   A. Concentration
   B. Viscosity
   C. Super-saturation
   D. Density

6. Fresh orange juice contains 12% (by weight) solids and the rest water 90% of the fresh juice is sent to an evaporator to remove water and subsequently mixed with the remaining 10% of fresh juice. The resultant product contains 40% solids. The kg of water removed from 1 kg fresh juice is__________________?

   A. 0.4
   B. 0.5
   C. 0.6
   D. 0.7

7. A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is__________________?

   A. 6000
   B. 24000
   C. 60000
   D. 48000

8. 200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 × 10-3 kg/m2.s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m2/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)?

   A. 0.5
   B. 0.05
   C. 0.1
   D. 0.15

9. 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

10. 1000 kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in kg is__________________?

    A. 520
    B. 200
    C. 400
    D. 500