## Machine Design MCQ Set 1

1. Relation between the slope of two operating line in the give figure.

a) Equal

b) Un equal

c) 1>2

d) 2>1

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2. Only small equipments is required for co-current process.

a) True

b) False

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3. Find the concentration representation in the equilibrium distribution curve given below.

a) Mole ratio

b) Mass ratio

c) Mole fraction

d) None of the mentioned

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4. Find the slope of the operating line from the figure below.

If, Ls,Gs- non diffusing solvent

X,Y- Concentrations in mole ratio

x,y- concentration in mole fraction

a) Ls/Gs

b) –Ls/Gs

c) Gs/Ls

d) –Gs/Ls

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5. Find the driving force at the point (P) in the equilibrium distribution curve given below.

a) Zero

b) Infinity

c) One

d) Greater than one

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6. The driving force line between the operating line and the equilibrium line depends on

a) Relative diffusion resistance

b) Relative mass resistance

c) Cumulative resistance

d) None of the mentioned

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7. Removal of ammonia from the air with water is an example of counter-current process.

a) True

b) False

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8. For Air-Water system Lewis Number equals to

a) Approx 1

b) 0

c) Infinity

d) 0 to 1

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## Machine Design MCQ Set 2

1. The Ponchon Savorit method is applicable for determining negligible heat loss.

a) True

b) False

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2. External reflux ratio is used for Ponchon Savorit method.

a) True

b) False

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3. Find the heat removed by the condenser if the net heat out of the condenser is 25000 J and the total moles are 25.

a) 1000 J

b) 10000 J

c) 5000 J

d) 2000 J

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4. From the enthalpy-concentration diagram find the location of heat removed by the condenser.

a) X

b) Y

c) Z

d) None of the mentioned

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5. Find the internal reflux ratio by analysing the below fractionator.

a) 0.8

b) 1.25

c) 1.2

d) 1

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6. Estimate the heat removed by the condenser.

a) 20 KJ/Kg

b) 22 KJ/Kg

c) 24 KJ/Kg

d) 0

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7. Find the distillate rate by analysing the fractionator given below.

a) 10 KJ

b) 20 KJ

c) 30 KJ

d) 40 KJ

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8. The fictitious stream is the difference in the flow rates of the nth tray.

a) True

b) False

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9. Ponchon Savorit method do not include enthalpy concentration diagram.

a) True

b) False

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10. Find the flow rate of liquid entering into the enriching section if the internal reflux ratio is 1.5 times min. Given minimum reflux ratio is 0.95 and the gas flow rate is 35 mol/hr.

a) 49.87 mol/hr

b) 22.167 mol/hr

c) 55.26 mol/hr

d) None of the mentioned

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## Machine Design MCQ Set 3

1. Device where two insoluble phases are brought into contact is known as

a) Trays

b) Stage

c) Cascade

d) Sieves

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2. Ideal stages are also known as

a) Equilibrium or Theoretical stages

b) Equilibrium or Actual stages

c) Differential or Theoretical stages

d) Differential or Actual stages

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3. More than one stages are interconnected to form

a) Trays

b) Sieves

c) Cascades

d) Multiple stage

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4. The main purpose of cascades is

a) To get maximum conversion

b) To increase mass transfer rates

c) To get more efficiency

d) None of the mentioned

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5. (Yn- Yn-1)/ (Yn*-Yn-1) is

a) Fractional overall

b) Murphree stage

c) Stage

d) Tray

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6. Find the number of stage(s)

Where,

Y- Mole Ratio of gas phase

X- Mole Ratio of liquid phase

a) 1

b) 2

c) 1 to 2

d) No stage

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7. Murphree efficiency is defined as the number of equilibrium stages to the number of real stages.

a) True

b) False

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8. Find the value of y in an ideal single stage absorber is used to remove ammonia from gas with water as solvent. Its representation is given below

Here,

y0=0.2, the molar gas flow rates of liquid and gas mixture in (moles/sec) are 4 and 2. The equilibrium relation between y and x is given by y = 0.2x. The solvent water is pure.

a) 1/10

b) 1/20

c) 2/110

d) 2/220

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9. ______________ is defined as the number of equilibrium stages to the number of real stages.

a) Murphree stage efficiency

b) Fractional overall efficiency

c) Stage efficiency

d) Overall efficiency

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10. Find the Murphree stage efficiency for the following co-current operation with equilibrium leaving gas phase concentration Y*= 0.8.

Where,

G and L are gas and liquid flow rates

Y and X are concentration in mole ratio (Y1=0.2, Y2=0.4, X1= 0.6, X2=0.8)

a) 25%

b) 50%

c) 75%

d) 100%

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## Machine Design MCQ Set 4

1. In which of the following conditions mass transfer will occur spontaneously? C and z is concentration and distance respectively.

a) dC/dz>0

b) dC/dz<0

c) dC/dz=0

d) None of the Mentioned

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2. Which among the following is always true for mass transfer to occur?

a) Difference in concentration

b) Difference in Pressure

c) Difference in temperature.

d) Difference in chemical potential.

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3. A solution contains 0.3 moles of solute A, 0.2 moles of B and 0.5 moles of C. What will be the mole fraction of A in the mixture?

a) 0.3

b) 0.2

c) 0.5

d) 1

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Paragraph for question Numbers (4-6)

A gas mixture containing 21% O_{2} and 79% N_{2} flows through a pipe of circular cross-section of diameter 2cm at atmospheric pressure. The velocity of O_{2} is 0.04m/s and N_{2} is 0.035m/s.

4. What is the value of molar average velocity (m/s) of the mixture?

a) 0.036

b) 0.035

c) 0.034

d) 0.033

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_{1}u

_{1}+C

_{2}u

_{2}+……….)/C =y

_{1}u

_{1}+y

_{2}u

_{2}….. = 0.21*0.04+0.79*0.035 =0.036

5. What will be the value of mass average velocity (m/s)?

a) 0.981

b) 0.891

c) 0.985

d) 0.857

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_{1}u

_{1}+ρ

_{2}u

_{2})/ ρ ρ

_{1}= (p

_{1}*M

_{1})/RT ρ= (p*M)/RT. Dividing these two equations ρ

_{1}/ ρ = (p

_{1}*M

_{1})/pM =(y

_{1}*M

_{1})/M M=y

_{1}*M

_{1}+y

_{2}*M

_{2}=0.79*28+0.21*32=28.84 Mass average velocity= (y

_{1}*M

_{1}*u

_{1}+y

_{2}*M

_{2}*u

_{2})/M = (0.21*32*0.04+0.79*0.035)/28.84 = 0.981

6. What is the value of Volume average velocity?

a) 0.036

b) 0.035

c) 0.034

d) 0.033

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7. In a gas mixture if molecular weights of all the species are equal than which one will be more, Mass average velocity or Molar average velocity?

a) Mass average velocity

b) Molar average velocity

c) Both will have the same value

d) Nothing definite can be said

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_{1}+x

_{2}+………+ x

_{n})=M (x

_{1}+x

_{2}+………+ x

_{n}=1) Mass average velocity=Σu

_{i}ρ

_{i}/ρ=u

_{i}Pu

_{i}/P Molar average velocity=Σc

_{i}u

_{i}/c=ρu

_{i}P

_{i}/P (P=cRT).

8. The velocity of various components of mixture(21% A, 78% B and 1% C) are:

Velocity is in the form: v⃗=xi+yj+zk

Velocity of component A= (0.1, 0, 0)

Velocity of component B= (0, 0.1, 0)

Velocity of component B= (0, 0, 0.1)

Calculate the value of average molar velocity?

a) (0.021, 0.078, 0.01)

b) (0.1, 0.1, 0.1)

c) (0, 0 ,0)

d) (0.079, 0.021, 0.01)

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_{1}u

_{1}+c

_{2}u

_{2}+c

_{3}u

_{3})/C.

9. Calculate the value of mass average velocity in the previous question?

a) (0.0235, 0.0764, 0.00007)

b) (0.021, 0.078, 0.01)

c) (0.1, 0.1 0.1)

d) (0.079, 0.021, 0.01)

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_{1}*M

_{1}*u

_{1}+y

_{2}*M

_{2}*u

_{2})/M.

10. For the calculation of Mass average velocity, which velocity of the molecule is used?

a) Instantaneous Velocity

b) Mean Velocity

c) Instantaneous Velocity as well as Mean Velocity

d) Bulk velocity of the mixture

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11. Which among the following can be the unit of Flux?

a) Kg*m-2*s-1

b) Kg*m2*s-1

c) Kg*m2*s1

d) Kg*m*s2

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12. A molecule in a mixture moves with a velocity of 0.03m/s in (+x) direction. The concentration of the particle is 0.5 mol/liter. A observer is running in (-x) direction with a velocity of 2m/s. calculate the value of molar flux (mol/m2.s) relative to the observer.

a) 0.015

b) 15

c) 1.015

d) 1015

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13. In the previous question what will be the value of flux (mol/m2.s) with respect to a stationary observer?

a) 0.015

b) 15

c) 1.015

d) 1015

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14. Under which of the following conditions mass average velocity and molar average velocity are equal?

a) In a very dilute solution

b) If molecular weights of all the species are equal

c) Always different

d) In dilute solutions as well as in solutions in which all components have same molecular weights

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15. The mass flow rate of a component in a mixture in X-direction is 2kg/s. The area vector at a particular cross-section is (1.1, 3.2, 5.4) cm2. Calculate the value of flux (kg/cm2.s) through the cross-section.

a) 0.31

b) 2.2

c) 1.82

d) 6.45

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## Machine Design MCQ Set 5

1. The ratio of mass concentration of species A to the total mass density of the mixture is known as

a) Mass density

b) Concentration

c) Mole fraction

d) Mass fraction

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_{a}/p.

2. For a binary mixture of species A and B, the mass average velocity is defined as

a) 2 p _{a} V _{a} + p _{b} V _{b}/ p

b) p _{a} V _{a} + p _{b} V _{b}/ p

c) p _{a} V _{a} + 2 p _{b} V _{b}/ p

d) p _{a} V _{a} + p _{b} V _{b}/ 2 p

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_{a}V

_{a}+ p

_{b}V

_{b}/ p

_{a}+ p

_{b }= p

_{a}V

_{a}+ p

_{b}V

_{b}/ p.

3. The ratio of number of moles of species A to the total number of moles of the mixture is known as

a) Mole fraction

b) Mass fraction

c) Partial pressure

d) Mass density

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_{a}/n.

4. A binary mixture of oxygen and nitrogen with partial pressures in the ratio 0.21 and 0.79 is contained in a vessel at 300 K. If the total pressure of the mixture is 1 * 10 ^{5} N/m^{2}, find molar concentration of oxygen

a) 8.42 * 10 ^{-1} kg mol/m^{3}

b) 8.42 * 10 ^{-2} kg mol/m^{3}

c) 8.42 * 10 ^{-3} kg mol/m^{3}

d) 8.42 * 10 ^{-4} kg mol/m^{3}

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^{5}/8341 * 300 = 8.42 * 10

^{-3}kg mol/m

^{3}.

5. For a binary mixture of species A and B, the molar average velocity is defined as

a) n _{a} V _{a} + n _{b} V _{b}

b) n _{a} V _{a} + n _{b} V _{b}/n

c) n _{a} V _{a} + n _{b} V _{b}/2 n

d) n _{a} V _{a} + 2 n _{b} V _{b}/n

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_{A}V

_{A}+ n

_{B}V

_{B}/n

_{A}+ n

_{B}= n

_{A}V

_{A}+ n

_{B}V

_{B}/n.

6. Given diagram shows diffusion of water vapor through air. Identify the correct statement

a) The water evaporates and diffuses downward

b) The water does not evaporates but diffuses upward

c) The water evaporates and diffuses upward

d) The water does not evaporates but diffuses downward

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7. A binary mixture of oxygen and nitrogen with partial pressures in the ratio 0.21 and 0.79 is contained in a vessel at 300 K. If the total pressure of the mixture is 1 * 10 ^{5} N/m^{2}, find overall mass density

a) 4.156 kg/m^{3}

b) 3.156 kg/m^{3}

c) 2.156 kg/m^{3}

d) 1.156 kg/m^{3}

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^{3}and for nitrogen = 0.887 kg/m

^{3}.

8. A binary mixture of oxygen and nitrogen with partial pressures in the ratio 0.21 and 0.79 is contained in a vessel at 300 K. If the total pressure of the mixture is 1 * 10 ^{5} N/m^{2}, find molar fraction of nitrogen

a) 0.79

b) 0.21

c) 0.23

d) 0.13

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9. A binary mixture of oxygen and nitrogen with partial pressures in the ratio 0.21 and 0.79 is contained in a vessel at 300 K. If the total pressure of the mixture is 1 * 10 ^{5} N/m^{2}, find mass fraction of oxygen

a) 0.133

b) 0.233

c) 0.333

d) 0.433

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10. A binary mixture of oxygen and nitrogen with partial pressures in the ratio 0.21 and 0.79 is contained in a vessel at 300 K. If the total pressure of the mixture is 1 * 10 ^{5} N/m^{2}, find the average molecular weight of the mixture

a) 28.84

b) 29.84

c) 30.84

d) 31.84