## Interview MCQ Set 1

1. What is the role of Energy-separating agent (ESA)?

a) Involves heat transfer

b) Involves mass transfer

c) Acts as an agitator

d) Is a catalyst

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2. Which of the following is NOT a disadvantages of using a mass-separating agent (MSA) ?

a) Need for additional separator to remove MSA

b) Possible MSA contamination

c) Difficult design procedures

d) Need for large quantities of MSA

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3. Which separation process is used when the volatility differences is too small between the species?

a) Flash vaporization

b) Stripping

c) Extractive distillation

d) Liquid-Liquid extraction

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4. What is added when it is difficult to condense vapors leaving the distillation column at top?

a) Adsorbent

b) Absorbent

c) Agitator

d) ESA

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5. Which separation technique shall be used to remove ethane and lower molecular weight hydrocarbons for LPG production?

a) Flash vaporization

b) Distillation

c) Reboiled absorption

d) Stripping

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6. Which separation technique shall be employed to separate acetone and methanol?

a) Extractive distillation

b) Stripping

c) Liquid-Liquid extraction

d) Evaporation

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7. In azeotropic distillation, why is an entrainer added?

a) To increase the boiling point of the mixture

b) To decrease the boiling point of the mixture

c) To form a minimum boiling point azeotrope

d) To form two immiscible phases

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8. When is the liquid-liquid extraction preferred over distillation?

a) When the distillation apparatus is not available

b) Distillation apparatus is costly

c) When there too very high difference in the boiling points.

d) When the liquid mixture is temperature sensitive

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9. Which of the following solvents can be added during separation of Isopropyl alcohol and water?

a) Methanol

b) Ethanol

c) Benzene

d) Alcoholic KOH

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10. How is sulphur separated from its impurities?

a) Desublimation

b) Sublimation

c) Crystallization

d) Drying

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11. Where is the technique of leaching used?

a) Research laboratories

b) Soap industry

c) Pharmaceutical industry

d) Metallurgical industry

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## Interview MCQ Set 2

1. What is a nomograph?

a) A graph containing relationship between two quantities

b) A graph containing relationship between three quantities

c) A graph containing relationship between three or more quantities

d) A graph containing diagrams

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2. The convergence pressure depends on what?

a) Densities of the components

b) Amounts of the components

c) Melting points of the components

d) Boiling points of the components

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3. What is the convergence pressure for narrow boiling point mixtures?

a) less than 5000psia

b) less than 2500psia

c) less than 1000psia

d) less than 500psia

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4. Why are there no charts available for liquid-liquid distribution?

a) The values are different every time

b) Because of pronounced effect of composition

c) Because the distribution is tough to find

d) There is no convergence pressure

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5. What estimation is available for dilute solutions that are ternary and contain almost immiscible solvents?

a) A tabular distribution of partition coefficients by robins

b) A tabular distribution of partition coefficients by keller

c) A tabular distribution of partition coefficients by Haden

d) A tabular distribution of partition coefficients by Grayson

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6. What Is NOT the use of plots of thermodynamic properties?

a) Used to establish correlations.

b) Used to make general observation

c) Used to extrapolate and find unknown quantities

d) Used to know the purity

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7. Which equation is fitted in the plot of vapor pressure versus temperature?

a) Roult’s law

b) Newton’s law

c) Antoine Equation

d) Gibb’s equation

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8. How are Nomographs used?

a) They give the direct reading

b) By joining the lines and extrapolating

c) By finding out points, joining the lines and extrapolating

d) Nomographs are ancient and thus not used

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9. If the partial vapor pressure of the component is 1000pa in the gaseous mixture and the vapor pressure of pure component is 2000pa what is the mole fraction of the solute?

a) 2

b) 1

c) 1.5

d) 0.5

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_{s}

^{i}/P. Hence xi = 1000/2000=0.5.

10. What is the K-value if the partial vapor pressure of the component is 360Pa in gaseous mixture and the vapor pressure of pure component is 500Pa.

a) 0.43

b) 0.55

c) 0.72

d) 0.88

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_{s}

^{i}/P .Hence K=260/500=0.72.

## Interview MCQ Set 3

1. Which of the following is an advantage of using the continuous countercurrent operation?

a) Maximizes the average driving force for transport

b) Maximizes the efficiency

c) Maximizes the cost

d) Minimizes the cost

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2. What relationship is true about solute free mass flow rates?

a) F/S less than K less than D/S

b) D/S less than K less than F/S

c) F/S less than D/S less than K

d) D/S less than F/S less than K

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3. What is untrue for Mcabe thiele method for adsorption at elevated temperatures?

a) F/S cannot be greater than D/S

b) The two operating lines must intersect at the point (qR , cR )

c) Desorption line is placed below adsorption line by elevating temperature

d) Elevated pressure can also be used

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4. If K_{A}= 20, K_{B}=30, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 0-0.81

c) 0.81-1

d) 0.9-1

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_{a}/K

_{b}, the limit is square root of 20/30=0.81.

5. If K_{A}= 40, K_{B}=50, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 0-0.81

c) 0.81-1

d) 0.89-1

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_{a}/K

_{b}, the limit is square root of 40/50=0.89.

6. If K_{A}= 20, K_{B}=80, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 1-0.5

c) 0.81-1

d) 0.9-1

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_{a}/K

_{b}, the limit is square root of 20/80=0.5.

7. If K_{A}= 36, K_{B}=100, what is the permissible values ,what is the safety margin for TMB model is:

a) 1-0.6

b) 0-0.81

c) 0.66-1

d) 0.36-1

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_{a}/K

_{b}, the limit is square root of 36/100=0.6.

8. If K_{A}= 50, K_{B}=60, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 1-0.89

c) 0.91-1

d) 0.97-1

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_{a}/K

_{b}, the limit is square root of 50/60=0.91.

9. If K_{A}= 40, K_{B}=80, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.5

b) 1-0.5

c) 0.70-1

d) 0.5-1

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_{a}/K

_{b}, the limit is square root of 40/80=0.70.

10. If K_{A}= 10, K_{B}=60, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.40

b) 1-0.167

c) 0.45-1

d) 0.407-1

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_{a}/K

_{b}, the limit is square root of 10/60=0.40z.

## Interview MCQ Set 4

1. What does N stand for?

a) Number of processes

b) Number of stages

c) Number of equipment

d) Ratio of feed to product

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2. When does the graphical method become tedious?

a) When there are too many solvents

b) When too many stages are involved

c) When more than one solute is adsorbed or stripped

d) When the solute to be stripped is unknown

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3. Which method is applied when graphical method is unsuitable?

a) Keller method

b) Newton’s method

c) Distillation method

d) Kremser method

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4. What is the formula for fraction of the solute i absorbed?

a) A _{i}^{ N+1} – 1/ A _{i} ^{N+1} –A _{i}

b) A _{i} ^{ N+1} – A _{i} / A _{i} ^{ N+1} –1

c) S _{i} ^{ N+1} – S _{i} / S _{i} ^{ N+1} –1

d) S _{i} ^{ N+1} – A _{i} / S _{i} ^{ N+1} –1

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_{i}

^{ N+1}– A

_{i}/ A

_{i}

^{ N+1}–1 where A

_{i}= L/K i V.

5. What is the formula for fraction of the solute i stripped?

a) A _{i}^{ N+1} – 1/ A _{i} ^{N+1} –A _{i}

b) A _{i} ^{ N+1} – A _{i} / A _{i} ^{ N+1} –1

c) S _{i} ^{ N+1} – S _{i} / S _{i} ^{ N+1} –1

d) S _{i} ^{ N+1} – A _{i} / S _{i} ^{ N+1} –1

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_{i}

^{ N+1}– S

_{i}/ S

_{i}

^{ N+1}–1 Where S

_{i}= K

_{i}V/L.

6. Which of the following does not give a correct expression for K _{i} ?

a) Roult’s law

b) Henry’s law

c) Modified Roult’s law

d) Gas law

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7. When is the Roult’s law used?

a) Ideal solutions involving solutes at sub-critical temperatures

b) Non-ideal solutions involving solvents at sub-critical temperatures

c) Ideal solution involving solutes at critical temperatures

d) Non-ideal solutions involving solutes at critical temperatures

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_{i}= P

_{s}

^{i}/P is applied for Ideal solutions involving solutes at sub-critical temperatures.

8. Which equation is used for solutes at supercritical temperatures?

a) Roult’s law

b) Henry’s law

c) Modified Roult’s law

d) Gas law

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_{i}=H

_{i}/P is used for solutes at supercritical temperatures.

9. Which equation is sued for sparingly soluble solutes at sub-critical temperatures?

a) Roult’s law

b) Henry’s law

c) Modified Roult’s law

d) Solubility equation

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_{i}= P

_{s}

^{i}/x * i P is used for sparingly soluble solutes at sub-critical temperatures.

10. What is the formula for solute absorption factor?

a) A_{i} = LV/K_{i}

b) S_{i} = K_{i} V/L

c) A_{i} =L/K_{i} V

d) S_{i} = K_{i} /LV

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_{i}=L/K

_{i}V is the formula for solute absorption factor where L and V are the feed rates.

## Interview MCQ Set 5

1. In crystallization, solvent should dissolve large amount of solute at:

a) Room temperature

b) Boiling point

c) Freezing point

d) Slip melting point

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2. Insoluble impurities during crystallization are removed by:

a) Decantation

b) Filtration

c) Distillation

d) Fractional crystallization

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3. The crystals obtained in crystallization are dried by:

a) Dryer

b) Oven

c) Filter paper

d) Exposing to sun

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4. Which of the following is not an assumption of MSMPR model?

a) Perfect mixing of the magma

b) No crystal breakage

c) Continuous, steady-flow, steady-state operation

d) Crystals are of various sizes.

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5. What is the number of crystals per unit mass of crystals if

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 5

a) 0.01

b) 0.7

c) 0.6

d) 0.8

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_{v}ρL

^{3}, hence N=0.01.

6. What is the number of crystals per unit mass of crystals if

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.05

a) 0.01

b) 0.7

c) 0.6

d) 100000

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_{v}ρL

^{3}, hence N=1000000.

7. What is the number of crystals per unit mass of crystals if

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.78

a) 1.56

b) 2.34

c) 2.56

d) 0.8

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_{v}ρL

^{3}, hence N=2.56.

8. What is the number of crystals per unit mass of crystals if

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.56

a) 5.67

b) 6.78

c) 7.11

d) 9.56

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_{v}ρL

^{3}, hence N=7.11.

9. What is the number of crystals per unit mass of crystals if

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.67

a) 1.56

b) 7.89

c) 4.22

d) 4.15

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_{v}ρL

^{3}, hence N=4.15.

10. What is the nucleation rate if

Mass of production of crystals C=0.5kg

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.5

volume of mother liquor in magma V= 1m^{3}

a) 0.5

b) 1.5

c) 1.8

d) 2.7

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_{v}ρL

^{3}V, hence rate= 1.8.

11. What is the nucleation rate if

Mass of production of crystals C=0.5kg

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.5

volume of mother liquor in magma V= 0.5m^{3}

a) 5.4

b) 3.6

c) 1.8

d) 2.7

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_{v}ρL

^{3}V, hence rate= 3.6.

12. What is the nucleation rate if

Mass of production of crystals C=0.5kg

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.6

volume of mother liquor in magma V= 1m^{3}

a) 1.45

b) 1.5

c) 1.07

d) 1.04

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_{v}ρL

^{3}V, hence rate= 1.04.

13. What is the nucleation rate if

Mass of production of crystals C=0.5kg

Volume shape factor f_{v}= 0.5

Density of particle= 0.5kg/m^{3}

Characteristic size of crystal L= 0.5

volume of mother liquor in magma V= 1m^{3}

a) 0.5

b) 15

c) 1.8

d) 18

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_{v}ρL

^{3}V, hence rate= 18.

14. What is the nucleation rate if

Mass of production of crystals C=10kg

Volume shape factor f_{v}= 0.5

Density of particle= 5kg/m^{3}

Characteristic size of crystal L= 0.5

volume of mother liquor in magma V= 1m^{3}

a) 9

b) 18

c) 180

d) 36

### View Answer

_{v}ρL

^{3}V, hence rate= 180.