chemical engineering MCQs – Page 90

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
1781. The most efficient cooling tower out of the following is_____________________?
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A. Induced draft

B. Natural draft

C. Forced draft

D. Atmospheric

1782. Compound A is extracted from a solution of A + B into a pure solvent S. A Co-current unit is used for the liquid-liquid extraction. The inlet rate of the solution containing A is 200 moles of B/hr.m2 and the solvent flow, rate is 400 moles of S/m2. hr. The equilibrium data is represented by Y = 3X2 , where Y is in moles of a A/moles of B and X is in moles A/moles of S. The maximum percentage extraction achieved in the unit is_________________________?
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A. 90%

B. 50%

C. 70%

D. 25%

1783. Laboratory determination of the diffusivity of vapor is done by __________________ method?
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A. Wikes

B. Wetted wall column

C. Winkelmanns

D. Gillilands

1784. If the specific heats of a gas and a vapor are 0.2KJ/Kg.K and 1.5 KJ/Kg.K respectively, and the humidity is 0.01; the humid heat in KJ/Kg. is________________?
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A. 0.31

B. 0.017

C. 0.107

D. 0.215
1785. The value of NA/(NA + NB), for steady state equimolal counter diffusion of two gases A and B is____________?
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A. 2

B. 1

C. 0.5

D. ?
1786. In the layout plan for a vacuum distillation unit, operating at 60 mm Hg, supported by a barometric condenser, the appropriate place for the location of vacuum drum for collecting the distillate will be_____________________?
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A. At ground level

B. 2 metres above the ground

C. 5 metres above ground

D. 10 metres above ground

1787. A binary mixture of benzene and cyclohexane is separated by___________________?
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A. Flash vaporisation

B. Extractive distillation

C. Solvent extraction

D. Ordinary distillation

1788. In Azeotropic mixture, the equilibrium vapour composition is____________________?
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A. More than liquid composition

B. Less than liquid composition

C. Independent of pressure

D. Same as liquid composition
1789. Free flowing granular materials can be best dried in a __________________ drier?
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A. Drum

B. Rotary

C. Freeze

D. Cylinder

1790. The drying time between fixed moisture content within diffusion controlled falling rate period is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid) ?
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A. T

B. T3

C. T2

D. ?T

1791. Which of the following adsorbent is used to decolourise yellow glycerine ?
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A. Alumina

B. Fullers earth

C. Activated carbon

D. Silica gel

1792. Paper industry employs _______________ driers?
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A. Fluidised bed

B. Cylinder

C. Rotary

D. Spray

1793. For a distillation column operating at minimum reflux, the_______________________?
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A. Number of plates required will be maximum

B. None of these

C. Reflux ratio will be maximum

D. Concentration of liquid and vapour leaving a plate will be same

1794. A coalescer in a mixer-settler liquid-liquid extraction column______________________?
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A. Helps in increasing the bubble size entering the settler

B. All a, b, & c

C. Comprises of thin bed of substances of extended surface having high porosity

D. Helps in increasing the settling rate of the bubbles

1795. Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion, if____________________?
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A. There is equimolar counter diffusion

B. Diffusion of A is in stagnant medium B

C. Mass transfer is accompanied by reaction

D. Molecular mean free path is high

1796. Pick out the wrong statement ?
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A. Co-current absorbers are usually used, when the gas to be dissolved in the liquid is a pure

B. stance

C. In case of gas absorption, HETP is equal to HTU, when both the operating line & the

D. ilibrium lines are parallel

E. Hatta number is important in case of gas absorption with chemical reaction

F. In actual practice, absorption is an endothermic process, while stripping is an exothermic
1797. Dew point of an air-water vapor mixture_________________?
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A. nt parallel to the temperature axis and to the saturation curve

B. At constant humidity & total pressure is fixed

C. All A , B. & C.

D. Corresponding to any point on the humidity chart is obtained by projecting a line through this

E. Decreases with decrease in pressure

1798. The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling ?
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A. Liquid side

B. Gas side

C. Interfacial

D. Both liquid and gas side

1799. A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids))_____________?
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A. M ln(Xo/XF)

B. MXo ln(Xo/XF)

C. M(Xo/XF)

D. M(Xo XF)

1800. Pick out the wrong statement. Raoults law does not apply, when the______________________?
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A. Size of component molecules are not equal

B. mation of solution

C. Attractive forces between like and unlike molecules in the solution are approximately equal

D. Component molecules are non-polar

E. Chemical combination or molecular association between unlike molecules takes place in the