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

2821. A catalyst promoter_________________?
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A. All A., B. and C.

B. Itself has very high activity

C. Acts as a catalyst support

D. Improves the activity of a catalyst
2822. A catalyst in a chemical reaction____________________?
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A. Alters the reaction mechanism

B. Increases the frequency of collisions of reacting species

C. All A., B. and C.

D. Decreases the activation energy

2823. For the irreversible elementary reactions in parallel as shown in the bellow figure, the rate of disappearance of X is equal to_______________?
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A. CA (K1 + K2)/2

B. CA . K1/2

C. CA (K1 + K2)

D. CA . K2/2

2824. A catalyst is said to be a negative catalyst, if it ___________________?
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A. Reduces the value of equilibrium constant

B. Retards the rate of reaction

C. Does not initiate the reaction

D. All A., B. and C.

2825. What is the maximum possible value of FR(mole/sec.) ?
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A. 2/3

B. 3-Jan

C. 2-Jan

D. 2

2826. The dispersion number of perfect mixed flow is__________________?
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A. < 2100

B. > 150

C. 0

D. ?
2827. What is the order of a chemical reaction whose rate is deter-mined by the variation of one concentration term only ?
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A. Second

B. Third

C. First

D. Zero

2828. The gas phase reaction 2A ? B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is _______________________?
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A. 5/8

B. 3-Feb

C. 3-Jan

D. 8-Mar

2829. Arrhenius equation represents graphically the variation between the ______________ and temperature?
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A. Rate constant

B. Frequency factor

C. Rate of reaction

D. Activation energy

2830. With increase in temperature, the rate constant obeying Arrhenius equation____________________?
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A. Can either increase or decrease; depends on the frequency factor

B. Decreases exponentially

C. Decreases

D. Increases

2831. When a high liquid hold up is required in a reactor for gas liquid reaction, use ______________ column?
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A. Packed

B. Spray

C. Tray

D. Bubble
2832. The value of Steric factor P in the equation k = PZeE/RT usually ranges from ______________________?
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A. 1.0 to 10-8

B. None of these

C. 1.1 to 102

D. 0.1 to 0.9

2833. Exposure of a photographic plate to produce a latent image is an example of _______________ reaction?
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A. Very slow

B. Very fast

C. Photochemical

D. Both B. and C.
2834. For every 10C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70C, the rate of reaction increases ______________ times?
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A. 16

B. 8

C. 12

D. 32

2835. For a tubular reactor with space time ? and residence time ?, the following statement holds good ?
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A. ? = ?, for a non-isothermal reactor

B. ? = ?, when the fluid density changes in the reactor

C. ? = ?, for an isothermic tubular reactor in which the density of the process fluid is constant

D. ? and ? are always equal

2836. With increase in the space time of an irreversible isothermal reaction being carried out in a P.F. reactor, the conversion will________________?
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A. Increase

B. Decrease

C. Remain same

D. Data in insufficient; cant be predicted

2837. Fractional conversion _____________ with increase in pressure for ammonia synthesis reaction i.e., N2 + 3H2 ? 2NH3?
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A. Unpredictable from the data

B. Decreases

C. Remains unchanged

D. Increases
2838. A reactor is generally termed as an autoclave, when it is a_____________________?
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A. Atmospheric pressure tank reactor

B. High pressure tubular reactor

C. Atmospheric pressure CSTR

D. High pressure batch reactor
2839. Given, 3H2 + CO = CH4 + H2O, KP = 101.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 101.17 the KP for the reaction CO + H2O = CO2 + H2 is __________________?
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A. 103.01

B. 100.67

C. 10-3.01

D. 10-0.67

2840. The enzyme which can catalyse the conversion of glucose to ethyl alcohol is ___________________?
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A. Maltase

B. Zymase

C. Invertase

D. Diastase

2841. A second order liquid phase reaction, A ? B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is_______________________?
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A. d(VCA)/dt = F (CAF CA) kCA2V

B. d(VCA)/dt = -F (CAF CA) kCA2V

C. d(VCA)/dt = FCAF kCA2V

D. d(VCA)/dt = -FCA kCA2V

2842. For all positive reaction orders for a particular duty ?
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A. Reactor size is independent of the type of flow

B. Mixed reactor is always larger than the plug-flow reactor

C. Density variation during reaction affects design

D. Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order

2843. Promoter is added to the catalyst to improve its____________________?
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A. Porosity

B. Sensitivity

C. Surface area

D. None of these

2844. The extent of a reaction is ___________________?
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A. Dimensionless

B. All of the above

C. Depends on the stoichiometric co-efficient

D. Different for reactants and products

2845. In a chemical reaction, represented by as shown in the bellow figure, it is observed that the (i) Rate of reaction increases by a factor of 4 on doubling the concentration of the reactant. (ii) Rate of reaction increases by a factor of 9 on trebling the concentration of the reactant. Then the rate of the reaction is proportional to(where, CA = concentration of the reactant)_____________________?
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A. CA4

B. CA2

C. CA

D. CA3

2846. Half life period of a chemical reaction is_________________?
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A. None of these

B. Half of the residence time of a reaction

C. Half of the space time of a reaction

D. The time required to reduce the concentration of the reacting substance to half its initial value
2847. The minimum energy required to allow a chemical reaction to proceed is termed as the threshold energy . Chemical reactions with low activation energy are ________________?
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A. Mostly irreversible

B. Highly temperature sensitive

C. Insensitive to temperature changes

D. Always irreversible

2848. Which of the following is the most suitable for very high pressure gas phase reaction ?
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A. Tubular flow reactor

B. Stirred tank reactor

C. Batch reactor

D. Fluidised bed reactor

2849. A pulse tracer is introduced in an ideal CSTR (with a mean residence time I) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be__________________?
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A. 0.693?

B. 2?

C. 0.5?

D. ?/0.693

2850. A reaction which is catalysed by an acid is also catalysed by any substance, which has a tendency to _________________?
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A. None of these

B. Lose a proton

C. Gain a proton

D. Lose an electron