Engineering Questions with Answers - Multiple Choice Questions
Food Engineering MCQ’s – Unit Operations – Crystallization-1
1 - Question
Celinium Sulphate is an exception of the solubility curve. When the temperature is increased, its solubility decreases.
a) True
b) False
View Answer
Explanation: Celinium Sulphate is an exception of the solubility curve. When the temperature is increased, its solubility decreases.
2 - Question
Which of the following is NOT an important criteria for crystal formation?
a) Caking characteristics of the crystal
b) Moisture content
c) Shape
d) None of the mentioned
View Answer
Explanation: All the mentioned factors are important criteria for the formation of crystals.
3 - Question
Statement 1: The solubility of NaCl increases with the increase in temperature.
Statement 2: Crystal formation is hindered by nucleation taking place on the crystal surface.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: The solubility of NaCl increases with the increase in temperature. Crystal formation is hindered by nucleation taking place on the crystal surface. It should take place from within.
4 - Question
Statement 1: Solid food items containing water molecules are more soluble as the temperature increases.
Statement 2: This growth takes place in steps.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Solid food items containing water molecules are more soluble as the temperature increases. This growth takes place in steps.
5 - Question
Which of the following tells the significance of crystallization in food processing?
a) Consistency of food emulsions
b) A good feel of food inside the mouth
c) The physical stability of food
d) All of the mentioned
View Answer
Explanation: Consistency of food emulsions, a good feel of food inside the mouth and the physical stability of food, all have a significant effect on the food processing.
6 - Question
Statement 1: Crystallization is both a mass and heat transfer operation.
Statement 2: The crystals and mother liquor obtained from a crystallizer are called _____
a) True, nucleation
b) False, solid residue
c) True, magma
d) False, crystal growth
View Answer
Explanation: Crystallization is both a mass and heat transfer operation. The crystals and mother liquor obtained from a crystallizer are called magma.
7 - Question
Statement 1: Smaller particles dissolve as they have a larger surface area and larger particles grow.
Statement 2: The above process is called Ostwald ripening.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Smaller particles dissolve as they have a larger surface area and larger particles grow. The above process is called Ostwald ripening.
8 - Question
The ratio of concentration of a super saturated solution to a saturated solution is denoted by α’ which is stated by the Kelvin equation. How is it related to the crystal size and interfacial tension between solid and liquid?
a) Directly, indirectly
b) Indirectly, directly
c) Directly, directly
d) Indirectly, indirectly
View Answer
Explanation: Crystal size is indirectly related to α’ and interfacial tension between solid and liquid is directly related to α’.
9 - Question
Parameters affecting crystallization are ____________
a) Agitator speed
b) Population density
c) Purity of solution
d) All of the mentioned
View Answer
Explanation: All of the mentioned factors affect crystallization.
10 - Question
Which of the following facilitates crystallization?
a) Hot concentrated solution is cooled for crystals to form
b) Solution is concentrated by evaporation
c) Adiabatic evaporation and cooling
d) All of the mentioned
View Answer
Explanation: All of the mentioned ways are applicable for crystallization.
11 - Question
Statement 1: Batch crystallizers are used if the throughput is high.
Statement 2: The operating cost of batch crystallizers is high.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Batch crystallizers are used if the throughput is low. The operating cost of batch crystallizers is high.
12 - Question
Statement 1: Batch crystallizers use the concept of cooling of hot solution/magma.
Statement 2: Control of particle size is poor in a batch crystallizer.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Batch crystallizers use the concept of cooling of hot solution/magma. Control of particle size is poor in a batch crystallizer.
13 - Question
Statement 1: Batch crystallizers are used for jaggery.
Statement 2: Particle size is controlled by stirring and scraping the concentrate from the vessel for better heat transfer. a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Batch crystallizers are used for jaggery. Particle size is controlled by stirring and scraping the concentrate from the vessel for better heat transfer.
14 - Question
Scraped surface crystallizers can be used for viscous fluids up to 10000 cp.
a) True
b) False
View Answer
Explanation: Scraped surface crystallizers can be used for viscous fluids up to 10000 cp.
15 - Question
Which of the following is true about scraped surface crystallizers?
a) Expansion of capacity is easy
b) Can be used for a wide range of temperature differences
c) Smaller size, less installation cost
d) All of the mentioned
View Answer
Explanation: Scraped surface crystallizers are small in size and have a low installation cost. They can be used for a wide range of temperature differences. Expansion of capacity is easy as more units can be conveniently added.