chemical engineering MCQs – Page 141

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 Review each marked answer and report any item that may be outdated or unclear.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

2801. In Langmuir treatment of adsorption,_________________?
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A. Extent of adsorption is more than one complete monomolecular layer on the surface

B. the rate of adsorption per site</strong>

C. raction between the adsorbed molecule

D. Whole surface of the catalyst does not have the same activity for adsorption and there is

E. Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect

F. All the adsorption does not take place by the same mechanism

2802. The energy of activation of a chemical reaction ?
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A. Is same as heat of reaction at constant pressure

B. Is the minimum energy which the molecules must have before the reaction can take place

C. Varies as fifth power of the temperature

D. Both B. and C.

2803. Cold shot cooling is only practical when the feed temperature is ______________ than the reaction temperature?
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A. Higher

B. Lower

C. Much lower

D. Much higher

2804. A batch reactor is characterised by ____________________?
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A. Constant residence time

B. Variation in reactor volume

C. Variation in extent of reaction and properties of the reaction mixture with time

D. Very low conversion

2805. Catalyst is a substance, which ________________ chemical reaction?
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A. Decreases the speed of a

B. Can either increase or decrease the speed of a

C. Increases the speed of a

D. Alters the value of equilibrium constant in a reversible

2806. What is the order of chemical reaction as shown in the bellow figure, if it is found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B were doubled and quadrupled when the concentrations of both B & C were doubled ?
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A. 3

B. 4

C. 2

D. 1

2807. If Thiele modulus is ________________, then the pore diffusion resistance in a catalyst may be considered as negligible?
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A. < 0.5

B. ?

C. > 0.5

D. 0

2808. Which of the following fixes the volume of a batch reactor for a particular conversion and production rate ?
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A. Operating conditions (e.g. pressure and temperature)

B. None of these

C. Rate constant

D. Density of mixture

2809. Mean residence time is equal to the space time, when_________________?
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A. There is no change in number of moles in gaseous reaction

B. All A., B. and C.

C. The temperature, pressure and the density of reaction mixture remains constant throughout the

D. ctor

E. The feed rate is measured at temperature and pressure in the reactor

2810. The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line ?
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A. XA(1 XA)Vs ?

B. XA Vs . ?

C. XA/(1 XA)Vs ?

D. XA Vs ln ?

2811. An irreversible first order reaction is being carried out in a CSTR and PFR of same volume. The liquid flow rates are same. The relative conversion will__________________?
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A. Be more in CSTR than in PFR

B. Be more in PFR than in CSTR

C. Be same in both cases

D. Depend on the temperature

2812. The E curve for a non-ideal reactor defines the fraction of fluid having age between t and t + dt _____________________?
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A. Averaged over the inlet and outlet

B. At the inlet

C. In the reactor

D. At the outlet

2813. Which of the following resistances is not involved in a gas phase catalytic (gas-solid) reaction ?
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A. Ash resistance

B. Gas film and pore surface diffusion resistances for reactants

C. Surface phenomenon resistance

D. Gas film and pore surface diffusion resistances for products

2814. Fluid flow in a real packed bed can be approximated as ________________ model?
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A. Tank in series

B. Dispersion

C. Mixed flow

D. Plug flow

2815. Concentration of the limiting reactant (with initial concentration of a moles/litre) after time t is (a-x). Then t for a first order reaction is given by____________________?
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A. k. t = ln (a x)/a

B. k. t = x/a (a x)

C. k. t = ln a/(a x)

D. k. t = ln a (a x)/x

2816. In case of calcination of limestone, CaCO3 CaO + CO2, the addition of more of CaO will result in _______________ in the concentration of CO2?
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A. Unpredictable from the data

B. Increase

C. No change

D. Decrease

2817. The heat of reaction__________________?
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A. Depends on the pressure only

B. Depends on the mechanism of reaction only

C. Depends on both pressure and mechanism of reaction

D. Is independent of the mechanism of reaction

2818. Equilibrium of a chemical reaction as viewed by kinetics is a ______________ state?
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A. Dynamic unsteady

B. None of these

C. Dynamic steady

D. Static steady

2819. For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by __________________?
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A. None of the above

B. A step function

C. A Dirac delta function

D. A ramp function

2820. What is the dispersion number for a CSTR ?
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A. 1

B. 0

C. ?

D. < 1

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