chemical engineering Mcqs
2851. Organic catalysts differ from the inorganic catalyst in the sense that the former is________________?
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A. Proteinous in nature

B. Active at very high temperature only

C. Active at cryogenic temperatures only

D. Prohibitively costly

2852. A batch reactor suffers from following disadvantage ?
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A. All A., B. and C.

B. High labour and handling cost

C. Poor product quality control

D. High shutdown time requirement for emptying, cleaning and refilling

2853. Limiting reactant in a chemical reaction decides the____________________?
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A. Reaction speed

B. Rate constant

C. Equilibrium constant

D. Conversion
2854. Kinetics of a catalytic reaction can be best studied on a/an ______________ reactor?
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A. Integral (plug flow)

B. Differential (flow)

C. Mixed

D. Either A., B. and C.
2855. Vegetable oils are hydrogenated in a _______________ reactor?
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A. Plug flow

B. Homogeneous catalytic

C. None of these

D. Slurry
2856. The space time is equivalent to the holding time in a steady state mixed reactor for_____________________?
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A. Non-isothermal gas reaction

B. Gas reactions with changing number of moles

C. Constant fluid density systems

D. Variable fluid density systems

2857. In a CSTR _______________ varies with time ?
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A. Reaction rate

B. Concentration

C. Both A. & B.

D. Neither A. nor B.
2858. If pore diffusion is the controlling step in a solid catalysed reaction, the catalyst___________________?
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A. Porosity is of less importance

B. None of these

C. Porosity is very important

D. Internal surface area is utilised efficiently

2859. Oil is hydrogenated using nickel catalyst in a __________________ reactor?
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A. Batch

B. Slurry

C. Fluidised bed

D. Fixed bed

2860. For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the____________________?
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A. Catalyst size is reduced or the catalyst diffusivity is increased

B. Catalyst size is reduced or the catalyst diffusivity is reduced

C. Catalyst size is increased or the catalyst diffusivity is reduced

D. Catalyst size is increased or the catalyst diffusivity is increased

2861. A typical example of an exothermic reversible reaction conducted at high pressure in industry is____________________?
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A. Dehydration of ethanol

B. Methanol synthesis

C. Polymerisation of ethylene

D. Reformation of methane

2862. For a _____________ order reaction, the units of rate constant and rate of reaction are the same ?
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A. Zero

B. Fractional

C. First

D. Second

2863. The order of a chemical reaction is__________________?
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A. Always equal to the total stoichiometric number of reactants

B. An experimentally determined quantity

C. Never fractional

D. None of these

2864. If the rate of a chemical reaction becomes slower at a given temperature, then the__________________?
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A. Entropy changes

B. Free energy of activation is lower

C. Initial concentration of the reactants remains constant

D. Free energy of activation is higher
2865. Find a mechanism that is consistent with the rate equation and reaction given below ?
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A. A + B ? AB; AB + A ? A2B

B. A + A ? AA; AA + B ? A2B

C. A + B ? AB; AB + A ? A2B

D. A + A ? AA; AA + B ? A2B

E. #NAME?

2866. Which of the following does not produce a change in the value of rate constant of a reaction ?
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A. Concentration and catalyst

B. None of these

C. Temperature

D. Pressure

2867. The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is _____________________ that of mixed reactor?
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A. Unpredictable from the data

B. Equal to

C. Greater than

D. Smaller than
2868. Which of the following factors control the design of a fluid-solid reactor ?
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A. Flow patterns of solids and fluid in the reactor

B. Reaction kinetics for single particle

C. All A., B. and C.

D. Size distribution of solids being treated

2869. A chemical reaction is of zero order, when the reaction rate is (where, CA = concentration of reactant) ?
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A. None of these

B. ? 1/CA

C. ? CA

D. Independent of temperature

2870. For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of ?
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A. Ideal plug flow

B. Dead zone

C. Channelling

D. Bypass

2871. A plug-flow reactor is characterized by _____________________?
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A. High capacity

B. Constant composition and temperature of reaction mixture

C. Presence of axial mixing

D. Presence of lateral mixing
2872. Rate of a gaseous phase reaction is given by the reaction shown in the bellow figure. The unit of rate constant is__________________?
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A. (atm)-1.(hr)-1

B. atm.(hr)-1

C. (atm)-1

D. (hr)-1

2873. For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?
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A. [CA0/(1 + ?A XA)] (dXA/dt) = k

B. ?A . ln (1 XA) = k . t

C. -ln(1 XA) = kt

D. XA = k . t

2874. For a zero order reaction, the concentration of product increases with the _____________________?
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A. Increase of reaction time

B. Total pressure

C. Increase in initial concentration

D. Decrease in total pressure

2875. Which of the following is not a unit of reaction rate ?
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A. Mole formed/volume of catalyst) (time)

B. Moles for med/(surface of catalyst) (time)

C. None of these

D. Moles formed/volume of reactor) (time)

2876. The conversion for a first order liquid phase reaction. A ? B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be_____________________?
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A. 75

B. 100

C. 60

D. 90

2877. In which of the following reactions, the equilibrium will shift to the right, if the total pressure is increased ?
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A. N2O4 ? 2 NO2

B. H2 + Cl2 ? 2HCl

C. H2 + I2 ? 2HI

D. N2 + O2 ? 2NO
2878. For the same residence time, which one will give the maximum conversion ?
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A. Single tubular flow reactor (v = 5 litres)

B. Single stirred tank (v = 5 litres)

C. Two stirred tank (each of 2.5 litres) in series

D. Stirred tank followed by tubular flow reactor (each of 2.5 litres)

2879. Effectiveness factor E. of a catalyst pellet is defined as, E = (actual rate within pore of the catalyst)/(rate if not snowed by pore diffusion), Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus) ___________________?
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A. tan hT/T

B. None of these

C. tan hT/tan T

D. tan T/T

2880. The catalytic converter for conversion of SO2 to SO3 by contact process should have a feed with SO2 content between___________________?
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A. 7-10 %

B. 12-15 %

C. 20-25 %

D. 2-5 %

2881. Inversion of cane sugar is an example of ______________________?
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A. Bimolecular reaction with second order

B. Unimolecular reaction with first order

C. Bimolecular reaction with first order

D. Unimolecular reaction with second order

2882. The vessel dispersion number (D/?L) for plug flow is_________________?
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A. 0

B. 500

C. 750

D. ?

2883. Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2/sec.D1 = diffusion co-efficient; cm2/sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3/sec. V = volume, cm3.) ?
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A. Reduced time (vt/V)

B. Thiele modulus L ?(k/D1)

C. None of these

D. Reactor dispersion number (D/vL)

2884. In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO2 to SO3 is accomplished by a ______________ reaction ?
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A. Non-catalytic homogeneous

B. Non-catalytic heterogeneous

C. Catalytic homogenous

D. Catalytic heterogeneous

2885. Space velocity____________________?
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A. All A., B. and C.

B. Describes the extensive operating characteristics of a tubular flow reactor

C. Is the maximum feed rate per unit volume of reactor for a given conversion

D. Is a measure of the ease of the reaction

2886. Fractional conversion _________________ for an exothermic reversible chemical reaction, when the temperature is maximum?
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A. Decreases

B. Remains unchanged

C. Unpredictable from the data

D. Increases

2887. Effectiveness factor of a catalyst pellet is a measure of the _________________ resistance?
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A. Gas film

B. Chemical reaction

C. Pore diffusion

D. None of these

2888. Pure A in gas phase enters a reactor 50% of this A is converted to B through the reaction, A ? 3B. Mole fraction of A in the exit stream is______________________?
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A. 5-Jan

B. 1/3

C. 4-Jan

D. 2-Jan

2889. A first order irreversible reaction, A ? B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that _____________ in the two reactors?
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A. Both conversion as well as concentration are same

B. Conversion in both will be the same but concentrations will be different

C. Both the conversion as well as concentrations will be different

D. None of these

2890. For identical flow rate, feed composition and for elementary first order reactions, N equal sized mixed reactors in series with a total volume V gives the same conversion as a single plug flow reactor of volume V for constant density systems. This is true, when the value of N is ___________________?
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A. > 1

B. 1

C. ?

D. ? 1

2891. In an ideal P.F.R. at steady state conditions ___________________?
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A. There may be diffusion along the flow path

B. The composition of reactants remains constant along a flow path

C. The conversion of the reactant varies from point to point along a flow path

D. There is no lateral mixing of fluid

2892. Kinetics of a solid catalysed reaction can best be studied in a _________________ reactor?
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A. None of these

B. Plug-flow

C. Mixed

D. Batch

2893. The conversion for a second order, irreversible reaction (constant volume) as shown in the bellow figure, in batch mode is given by______________?
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A. (k2 . CA0 . t)2/ (1 + k2 . CA0 . t)

B. 1/(1 + k2 . CA0 . t)

C. (k2 . CA0 . t)/ (1 + k2 . CA0 . t)2

D. (k2 . CA0 . t)/ (1 + k2 . CA0 . t)
2894. A chemical reaction occurs, when the energy of the reacting molecules is ________________ the activation energy of reaction?
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A. Equal to

B. Less than

C. More than

D. Equal to or more than
2895. Rate of a chemical reaction is not affected by the____________________?
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A. Number of molecules of reactants taking part in the reaction

B. Temperature

C. Catalyst

D. Reactants concentration

2896. For the gaseous reaction 2A ? B, where the feed consists of 50 mole % A and 50 mole % inerts, the expansion factor is___________________?
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A. 1

B. -0.25

C. -0.5

D. 0

2897. Maximum equilibrium conversion for endothermic reaction is obtained at the ______________ temperature?
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A. Lowest possible

B. Highest possible

C. Intermediate

D. Room

2898. Time required for 50% decomposition of a liquid in an isothermal batch reactor following first order kinetics is 2 minutes. The time required for 75% decomposition will be about _______________ minutes?
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A. 4

B. 6

C. 10

D. 3

2899. Non-catalytic fluid-solid reactions are represented by _______________ model?
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A. Continuous reaction

B. Unreacted core

C. Both A. and B.

D. Neither A. and B.

2900. A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be ____________________ minutes?
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A. 12

B. 16

C. 8

D. 4