## Interview MCQ Set 1

1. What does the solid-liquid separation operation don’t involve?

a) Gravity sedimentation

b) Magnetic separation

c) Filtration

d) Centrifugation

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2. What process happens in leaching?

a) A solvent separates a mixture

b) Two solvents separate a mixture

c) A solvent selectively dissolves one of the component

d) The mixture is heated so that one solid sublimes and is separated.

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3. What happens in an ideal leaching stage of a mixture of A and B?

a) The solvent dissolves Some B and some A

b) The solvent dissolves none of A and all B

c) The solvent dissolves all of A and B, which makes separation easier

d) The solvent does not dissolves any of A and B

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4. What increases the solute concentration?

a) Increasing viscosity of the liquid phases

b) Decreasing viscosity of liquid phases

c) Increasing temperature of liquid phases

d) Decreasing temperature of liquid phases

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5. What is a eutectic point?

a) A temperature at which the mixture boils

b) The temperature at which the mixture gets out of equilibrium

c) The temperature at which the components have same molar flow rates

d) The temperature at which the mixture freezes

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6. What is needed because of crystals occluding liquid?

a) Centrifugation

b) Distillation

c) Drying step

d) Decantation

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7. What is correct about the hydrate?

a) A high hydrate exists at low temperatures and low hydrste is unlikely to exist

b) A low hydrate exists at high temperature and a low hydrate exists at high temperature

c) A high hydrate exists at high temperature and a low hydrate exists at high temperature.

d) A hydrate does not exist at high temperature

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8. What happens during adsorption process of solid-liquid separation?

a) The adsorbent adsorbs liquid in the interior and solid in the exterior

b) The adsorbent adsorbs liquid In the interior and the exterior

c) The adsorbent adsorbs solid in the interior and liquid in the exterior

d) The adsorbent adsorbs solid in the interior and the exterior

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9. Which laboratory methods give a rough prediction about adsorption-equilibrium curves?

a) Isobaric calculation

b) Flow charts

c) Adsorption isotherms

d) Absorption isotherms

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10. The freundlich equation is of the form:

a) q_{i} = Ac_{i} ^{(1/n)}

b) c_{B}Q=q*_{B}S

c) q_{i} = Ac_{i}^{(n)}

d) q_{i} = Ac_{i}

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_{i}= Ac

_{i}

^{(1/n)}which can be converted to y=mx + c by taking logarithms on both sides.

## Interview MCQ Set 2

1. Which of the following is Fourier law of heat conduction?

a) q _{z} = k*dT _{z}/dZ

b) q _{z} = – k*dT _{z} /dZ

c) q _{z} = k*T _{z} /dZ

d) q _{z} = k*dQ _{z} /dZ

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2. Which of the following is correct representation of Fick’s law of diffusion?

a) J _{z} = -D*dc _{a} /dz

b) J _{z} = -D*dT/ds

c) J _{z} = D*dc _{a} /dz

d) J _{z} = -D*c _{a} /dz

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3. What id D _{ab} called in the Fick’s law?

a) Thermal conductivity

b) Density coefficient

c) Diffusivity

d) Electrical conductivity

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_{ab}is called as mutual diffusion coefficient or diffusivity.

4. Which of the following formulae is right about molar flux?

a) N _{a} = x _{A} N – D _{ab} (dx _{a} /d z )

b) N _{a} = x _{A} N – (dx _{a} /d z )

c) N _{a} = x _{A} N – cD _{ab}

d) N _{a} = x _{A} N – cD _{ab} (dx _{a} /d z )

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_{a}= x

_{A}N – cD

_{ab}(dx

_{a}/d z ).

5. Which of the following is untrue about equimolar diffusion?

a) N _{a} + N _{b} =0

b) J _{a} = J _{b}

c) N=0

d) N _{a} = -cD BA (dx _{b} /dz)

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_{a}= J

_{b}durig equimolar diffusion.

6. Which of the following is FALSE about unimolar diffusion?

a) N b = N a

b) N= N a

c) N a = x a N a – cD ab (dx a /dz)

d) X b N a = cD ba (dx b /dz)

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7. Why does the diffusion of A with respect to B occur?

a) Due to concentration gradient

b) To to volume gradient

c) Due to velocity gradiet

d) Due to change in heat

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8. Which diffusion occurs when turbulent motion is there?

a) Molar diffusion

b) Eddy diffusion

c) Charge diffusion

d) No diffusion

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9. When is fick’s law applied?

a) For passive diffusion down the concentration gradient

b) Passive osmosis along concentration gradient

c) Active osmosis along concentration gradient

d) Active and passive movement of molecule along concentration gradient

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10. Which of the following is TRUE?

a) Mass transfer in ordinary mixture occurs due to temperature gradient

b) Mass transfer is proportional to the area the molecules travel

c) Net transfer stops when concentrations are equal

d) The mass transfer is proportional to the area normal to the direction of mass transfer.

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## Interview MCQ Set 3

1. When it is not assumed that the vapor and liquid leaving a stage are not at same temperature?

a) When pressure changes from stage to stage

b) When temperature changes from stage to stage

c) When concentration of solute changes from stage to stage

d) When concentration of vapor changes from stage to stage

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2. To determine the actual number of required plates for a trayed column, what must be used?

a) K values

b) Process efficiency

c) Stage efficiency

d) Equilibrium between vapor and liquid

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3. What is the formula for overall stage efficiency given by lewis?

a) E _{o} = N_{t} /N _{a}

b) E_{o} = N_{t} N _{a}

c) E_{o} = N_{t} -N _{a}

d) E_{o} = N_{t} +N _{a}

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_{o}= N

_{t}/N

_{a}, where E

_{o}is the fractional stage efficiency, N

4. The overall stage efficiency is not a complex function of which of the following?

a) Geometry and design of contacting trays

b) Flow rates and flow paths for liquid and vapor phases

c) Compositions and properties of vapor and liquid phases

d) Material of the tray used

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5. What is the height added above the top tray to remove the entrained liquid?

a) 2ft

b) 4ft

c) 6ft

d) 8ft

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6. What is the height added below the bottom tray for bottom surge capacity?

a) 4ft

b) 6ft

c) 8ft

d) 10ft

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7. When are the columns in series preferred?

a) If the estimated height is above 100ft

b) If the estimated height Is above 150ft

c) If the estimated height is above 250ft

d) If the number of trays are less

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8. What is the tallest column in the world?

a) 240ft

b) 248ft

c) 300ft

d) 338ft

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9. What are the actual numbers of required plates when the overall stage efficiency is 0.8 and the calculated equilibrium stages are 4?

a) 2

b) 3

c) 5

d) 7

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_{o}= N

_{t}/N

_{a}, N

_{a}= 4/0.8=5.

10. What are the actual numbers of required plates when the overall stage efficiency is 0.9 and the calculated equilibrium stages are 9?

a) 12

b) 11

c) 5

d) 10

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_{o}= N

_{t}/N

_{a}, N

_{a}= 9/0.9=10.

11. What are the actual numbers of required plates when the overall stage efficiency is 0.7 and the calculated equilibrium stages are 2.8?

a) 2

b) 4

c) 5

d) 7

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_{o}= N

_{t}/N

_{a}, N

_{a}= 2.8/0.7=4.

12. What are the actual numbers of required plates when the overall stage efficiency is 0.6 and the calculated equilibrium stages are 4.8?

a) 8

b) 3

c) 5

d) 7

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_{o}= N

_{t}/N

_{a}, N

_{a}= 4.8/0.6=8.

13. What is the overall stage efficiency if the calculated equilibrium stages are 8 and the actual plates required are 12?

a) 0.75

b) 0.6

c) 0.56

d) 0.12

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_{o}= N

_{t}/N

_{a}, E

_{o}= 8/12 = 0.75.

14. What is the overall stage efficiency if the calculated equilibrium stages are 9 and the actual plates required are 11?

a) 0.75

b) 0.82

c) 0.56

d) 0.12

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_{o}= N

_{t}/N

_{a}, E

_{o}= 9/1 = 0.82.

15. What is the overall stage efficiency if the calculated equilibrium stages are 7 and the actual plates required are 13?

a) 0.75

b) 0.6

c) 0.54

d) 0.12

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_{o}= N

_{t}/N

_{a}, E

_{o}= 7/13 = 0.54.

## Interview MCQ Set 4

1. Calculate concentration of solvent if

Concentration of impurity is W_{o}=1%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 4.5*10^{-4}

c) 16.6*10^{-3}

d) 4.15*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 8.3*10

^{-3}.

2. Calculate concentration of solvent if

Concentration of impurity is W_{o}=2%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 4.5*10^{-4}

c) 16.6*10^{-3}

d) 4.15*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 16.6*10

^{-3}.

3. Calculate concentration of solvent if

Concentration of impurity is W_{o}=0.5%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 4.5*10^{-4}

c) 16.6*10^{-3}

d) 4.15*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 4.15*10

^{-3}.

4. Calculate concentration of solvent if

Concentration of impurity is W_{o}=0.6%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.5*10^{-3}

b) 4.9*10^{-3}

c) 32.6*10^{-3}

d) 23*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 4.9*10

^{-3}.

5. Calculate concentration of solvent if

Concentration of impurity is W_{o}=0.7%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 7.8*10^{-4}

c) 78*10^{-3}

d) 5.8*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 5.8*10

^{-3}.

6. Calculate concentration of solvent if

Concentration of impurity is W_{o}=3%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 32.89*10^{-4}

c) 16.6*10^{-3}

d) 24.9*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 24.9*10

^{-3}.

7. Calculate concentration of solvent if

Concentration of impurity is W_{o}=0.8%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 79*10^{-4}

c) 6.64*10^{-3}

d) 7.9*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 6.64*10

^{-3}.

8. Calculate concentration of solvent if

Concentration of impurity is W_{o}=0.9%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 9.8*10^{-4}

c) 7.47*10^{-3}

d) 8*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 7.47*10

^{-3}.

9. Calculate concentration of solvent if

Concentration of impurity is W_{o}=0.4%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 3.32*10^{-4}

c) 6.63*10^{-3}

d) 4.15*10^{-3}

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_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 3.32*10

^{-3}.

10. Calculate concentration of solvent if

Concentration of impurity is W_{o}=1.5%

Solid liquid equilibrium distribution coefficient is K=0.7

z/l= 0.8

a) 8.3*10^{-3}

b) 4.5*10^{-4}

c) 12.45*10^{-3}

d) 9*10^{-3}

### View Answer

_{s}= W

_{o}(1-(1-K)exp(-K*z/l)), hence W

_{s}= 12.45*10

^{-3}.

## Interview MCQ Set 5

1. What do the pressure filtration devices consist that remains suspended while allowing the fluid in which the solids are suspended to pass through?

a) Semipermeable membrane

b) Mesh barrier

c) No barrier

d) Column

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2. The filtration models are based on which laws?

a) Pascals law

b) Roult’s law

c) Avogadro’s law

d) Darcy’s law

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3. Which of the following is the correct representation of the darcy’s law?

a) (-k/µ)(dp/dz)

b) (-kµ)(dp/dz)

c) (k/µ)(dp/dz)

d) (kµ)(dp/dz)

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4. Why a pump that delivers slurry to a filtration unit at constant pressure not a positive displacement pump?

a) Because it operates at variable floe rate

b) Because it operates at constant flow rates

c) Because the time of flow is different

d) Because the time of flow is same

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5. If the reported filter area A= 1m^{2}

Viscosity µ = 5*10^{-4}

Pressure difference = 100

And the intercept is 500

What is the value of medium’s resistance to flow?

a) 1*10^{8}

b) 5*10^{8}

c) 6*10^{8}

d) 2.5*10^{8}

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_{m}= ΔPA(intercept)/µ, hence R

_{m}=1*10

^{8}.

6. If the reported filter area A= 1m^{2}

Viscosity µ = 1*10^{-4}

Pressure difference = 100

And the intercept is 500

What is the value of medium’s resistance to flow?

a) 1*10^{8}

b) 5*10^{8}

c) 6*10^{8}

d) 2.5*10^{8}

### View Answer

_{m}= ΔPA(intercept)/µ, hence R

_{m}=5*10

^{8}.

7. If the reported filter area A= 1m^{2}

Viscosity µ = 5*10^{-4}

Pressure difference = 100

And the intercept is 3000

What is the value of medium’s resistance to flow?

a) 1*10^{8}

b) 5*10^{8}

c) 6*10^{8}

d) 2.5*10^{8}

### View Answer

_{m}= ΔPA(intercept)/µ, hence R

_{m}=6*10

^{8}.

8. If the reported filter area A= 1m^{2}

Viscosity µ = 2*10^{-4}

Pressure difference = 100

And the intercept is 500

What is the value of medium’s resistance to flow?

a) 1*10^{8}

b) 5*10^{8}

c) 6*10^{8}

d) 2.5*10^{8}

### View Answer

_{m}= ΔPA(intercept)/µ, hence R

_{m}=2.5*10

^{8}.

9. If the reported filter area A= 1m^{2}

Viscosity µ = 10*10^{-4}

Pressure difference = 100

And the intercept is 500

What is the value of medium’s resistance to flow?

a) 0.5*10^{8}

b) 23*10^{8}

c) 11*10^{8}

d) 5.3*10^{8}

### View Answer

_{m}= ΔPA(intercept)/µ, hence R

_{m}=0.5*10

^{8}.

10. If the reported filter area A= 1m^{2}

Viscosity µ = 5*10^{-4}

Pressure difference = 100

And the intercept is 700

What is the value of medium’s resistance to flow?

a) 12*10^{8}

b) 5.5*10^{8}

c) 9.5*10^{8}

d) 1.4*10^{8}

### View Answer

_{m}= ΔPA(intercept)/µ, hence R

_{m}=1.4*10

^{8}.