ChE Reaction

Question 1

Which of the following will give maximum gas conversion?

A. Fixed bed reactor.
B. Fluidized bed reactor.
C. Semi-fluidized bed reactor.
D. Plug-flow catalytic reactor.

Answer 1

C. Semi-fluidized bed reactor.

Question 2

__________ explains the mechanism of catalysis.

A. Activated complex theory
B. Collision theory
C. Thermodynamics
D. None of these

Answer 2

A. Activated complex theory

Question 3

The fractional volume change of the system for the isothermal gas phase reaction, A → 3B, between no conversion and complete conversion is

A. 0.5
B. 1
C. 2
D. 3

Answer 3

C. 2

Question 4

A catalyst

A. initiates a reaction.
B. lowers the activation energy of reacting molecules.
C. is capable of reacting with any one of the reactants.
D. cannot be recovered chemically unchanged at the end of a chemical reaction.

Answer 4

B. lowers the activation energy of reacting molecules.

Question 5

What is the order of a chemical reaction, A + 2B → C, if the rate of formation of ‘C’, increases by a factor of 2.82 on doubling the concentration of ‘A’ and increases by a factor of 9 on trebling the concentration of ‘B’?

A. 7/2
B. 7/4
C. 5/2
D. 5/4

Answer 5

A. 7/2

Question 6

For high conversion in a highly exothermic solid catalyzed reaction, use a __________ bed reactor.

A. fixed
B. fluidized bed reactor followed by a fixed
C. fixed bed reactor followed by a fluidized
D. fluidized

Answer 6

B. fluidized bed reactor followed by a fixed

Question 7

For every 10°C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70°C, the rate of reaction increases __________ times.

A. 8
B. 12
C. 16
D. 32

Answer 7

C. 16

Question 8

A first order reaction requires two equal sized CSTR. The conversion is

A. less when they are connected in series.
B. more when they are connected in series.
C. more when they are connected in parallel.
D. same whether they are connected in series or in parallel.

Answer 8

B. more when they are connected in series.

Question 9

In case of physical adsorption, the heat of adsorption is of the order of __________ kcal/kg-mole.

A. 100
B. 1000
C. 10000
D. 100000

Answer 9

B. 1000

Question 10

The most unsuitable reactor for carrying out reactions in which high reactant concentration favors high yields is

A. backmix reactor
B. plug flow reactor
C. series of CSTR
D. PFR in series

Answer 10

A. backmix reactor

Question 11

Pick out the wrong statement pertaining to space velocity of flow reactors.

A. The unit of space velocity is (time)^-1
B. The space velocity of 3 hr^-1 means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour.
C. The space velocity of 3 hr^-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor.
D. none of these.

Answer 11

C. The space velocity of 3 hr^-1 means that one third reactor volume

Question 12

A reactor is generally termed as an autoclave, when it is a

A. high pressure batch reactor.
B. atmospheric pressure tank reactor.
C. high pressure tubular reactor.
D. atmospheric pressure CSTR

Answer 12

A. high pressure batch reactor
(PHB P18-57)

Question 13

6 Kg of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO2 and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant?

A. 100%
B. 95%
C. 75%
D. 20%

Answer 13

B. 95%

Question 14

The rate constant of a chemical reaction decreases by decreasing the

A. pressure
B. concentration of reactants
C. temperature
D. duration of reaction

Answer 14

C. temperature

Question 15

__________ is the response curve for a step input signal from a reactor.

A. S-curve
B. C-curve
C. I-curve
D. none of these

Answer 15

A. S-curve

Question 16

Which of the following is the most suitable for very high pressure gas phase reaction?

A. Batch reactor
B. Tubular flow reactor
C. Stirred tank reactor
D. Fluidized bed reacto

Answer 16

B. Tubular flow reactor

Question 17

The reaction between oxygen and organic material is a/an __________ reaction.

A. exothermic
B. endothermic
C. biochemical
D. photochemical

Answer 17

A. exothermic

Question 18

With decrease in temperature, the equilibrium conversion of a reversible endothermic reaction

A. decreases
B. increases
C. remains unaffected
D. increases linearly with temperature

Answer 18

A. decreases

Question 19

In an exothermic chemical reaction, the reactants compared to the products have

A. higher temperature
B. more energy
C. less energy
D. same energy.

Answer 19

B. more energy

Question 20

A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length

A. decreases.
B. increases.
C. is at the highest allowable temperature throughout.
D. first increases and then decrease

Answer 20

C. is at the highest allowable temperature throughout.

Question 21

The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 °K to 500 °K. Assuming transition state theory is valid, the value of E/R is

A. 8987°K
B. 9210°K
C. 8764°K
D. 8621°K

Answer 21

C. 9210°K
(9656.627°K by calculation)

Question 22

A batch reactor is suitable for

A. achieving cent percent conversion of reactants into products.
B. large scale gaseous phase reactions.
C. liquid phase reactions.
D. obtaining uniform polymerization products in highly exothermic reactions.

Answer 22

C. liquid phase reactions.

Question 23

For a heterogeneous catalytic reaction

A. free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction.
B. a relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important.
C. the catalyst does not form an intermediate complex with the reactant.
D. the surface of the catalyst does not play an important role during reaction.

Answer 23

A. free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction.

Question 24

The increase in the rate of reaction with temperature is due to

A. increase in the number of effective collisions.
B. decrease in activation energy.
C. increase in the average kinetic energy of the reacting molecules.
D. none of these.

Answer 24

B. decrease in activation energy.
(PHB P7-6)

Question 25

A catalyst loses its activity due to A. loss in surface area of the active component. B. agglomeration of metal particles caused by thermal sintering of the solid surface. C. covering of the catalytic active sites by a foreign substance. D. all (a), (b) and (c).

Answer 25

D. all (a), (b) and (c).

Question 26

'N' plug flow reactors in series with a total volume 'V' gives the same conversion as a single plug flow reactor of volume 'V' for __________ order reactions. A. first B. second C. third D. any

Answer 26

D. any

Question 27

For a zero order chemical reaction, the A. half life period is directly proportion to the initial concentration of the reactants. B. plot of products concentration with time is a straight line through the origin. C. products concentration increases linearly with time. D. all (a), (b) and (c).

Answer 27

D. all (a), (b) and (c).

Question 28

BET apparatus A. measures the catalyst surface area directly. B. operates at very high pressure. C. is made entirely of stainless steel. D. none of these.

Answer 28

D. none of these.

Question 29

Radioactive decay follows __________ order kinetics. A. first B. second C. third D. zero.

Answer 29

A. first

Question 30

The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the __________ energy. A. activation B. potential C. binding D. threshold

Answer 30

A. activation

Question 31

Pick out the correct statement. A. In catalytic reactions, the catalyst reacts with the reactants. B. A catalyst initiates a chemical reaction. C. A catalyst lowers the activation energy of the reacting molecules. D. A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction.

Answer 31

C. A catalyst lowers the activation energy of the reacting molecules.

Question 32

The dimensions of rate constant for reaction 3A → B are (l/gm mole)/min. Therefore the reaction order is A. 0 B. 1 C. 2 D. 3

Answer 32

C. 2

Question 33

Pick out the correct statement A. Reactions with high activation energies are very temperature sensitive. B. Chemical equilibrium is a static state. C. A photochemical reaction is catalyzed by light. D. A chemical reaction occurs when the energy of the reacting molecule is less than the activation energy of the reaction.

Answer 33

A. Reactions with high activation energies are very temperature sensitive.

Question 34

If the time required to complete a definite fraction of reaction varies inversely as the concentration of the reactants, then the order of reaction is A. 0 B. 1 C. 2 D. 3

Answer 34

C. 2

Question 35

Sulphuric acid is used as a catalyst in the A. hydrogenation of oils. B. gas phase oxidation of SO2 in chamber process. C. alkylation of hydrocarbons. D. none of these.

Answer 35

C. alkylation of hydrocarbons.

Question 36

Fractional conversion __________ with increase in pressure for ammonia synthesis reaction i.e., N2 + 3H2  2NH3. A. increases B. decreases C. remains unchanged D. unpredictable from the data

Answer 36

A. increases

Question 37

Pick out the wrong statement. A. The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively. B. Space time in a flow reactor is a measure of its capacity and is equal to the residence time when the density of reaction mixture is constant. C. Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty. D. In an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in longitudinal direction.

Answer 37

C. Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty.

Question 38

The reason why a catalyst increases the rate of reaction is that, it A. decreases the energy barrier for reaction. B. increases the activation energy. C. decreases the molecular collision diameter. D. none of these.

Answer 38

A. decreases the energy barrier for reaction.

Question 39

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. 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.

Answer 39

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

Question 40

The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the __________ energy. A. activation B. potential C. binding D. threshhold

Answer 40

A. activation

Question 41

When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is A. > 1 B. < 1 C. 1 D. 0

Answer 41

C. 1

Question 42

In an ideal tubular-flow reactor A. there is no mixing in longitudinal direction. B. mixing takes place in radial direction. C. there is a uniform velocity across the radius. D. all (a), (b) and (c).

Answer 42

D. all (a), (b) and (c).

Question 43

At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenius law is used. What will be this ratio, if transition state theory is used with the same value of E/R? A. 1.6 B. 2 C. 2.24 D. 2.5

Answer 43

D. 2.5 (by calculation: 1.6)

Question 44

__________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction. A. Gas film diffusion B. Ash diffusion C. Chemical reaction D. none of these

Answer 44

C. Chemical reaction

Question 45

An autothermal reactor is A. most suitable for a second order reaction. B. most suitable for a reversible reaction. C. completely self-supporting in its thermal energy requirements. D. isothermal in nature.

Answer 45

C. completely self-supporting in its thermal energy requirements.

Question 46

The rate constant of a first order reaction depends on the A. concentration of the reactant. B. temperature. C. concentration of the product. D. time.

Answer 46

B. temperature.

Question 47

A reaction in which one of the products of reaction acts as a catalyst is called a/an __________ reaction. A. catalytic B. autocatalytic C. photochemical D. none of these

Answer 47

B. autocatalytic

Question 48

The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is A. ∞ B. 0 C. 1 D. > 1

Answer 48

C. 1

Question 49

Which of the following will favor the reverse reaction in a chemical equilibrium reaction? A. Increasing the concentration of one of the reactants. B. Increasing the concentration of one or more of the products. C. Removal of at least one of the products at regular interval. D. None of these.

Answer 49

B. Increasing the concentration of one or more of the products.

Question 50

Conversion increases with increase in temperature in case of a an __________ reaction. A. autocatalytic B. irreversible C. reversible endothermic D. reversible exothermic

Answer 50

C. reversible endothermic

Question 51

A photochemical reaction is __________ light. A. initiated by B. accompanied with emission of C. catalyzed by D. used to convert heat energy into

Answer 51

A. initiated by

Question 52

Pick out the wrong statement. A. In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time. B. In a semi-batch reactor, one reactant is charged batch wise, while the other reactant is fed continuously. C. In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system. D. In a continuous flow reactor, both the reactants and the products flow out continuously.

Answer 52

C. In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system.

Question 53

In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation. A. adiabatic B. isothermal C. non-adiabatic D. none of these.

Answer 53

C. non-adiabatic

Question 54

'Unreacted core model' represents the reaction involving A. combustion of coal particles. B. roasting of sulphide ores. C. manufacture of carbon disulphide from elements. D. none of these.

Answer 54

B. roasting of sulphide ores.

Question 55

If a solid-gas non-catalytic reaction occurs at very high temperature, the rate controlling step is the __________ diffusion. A. film B. ash layer C. pore D. none of these

Answer 55

A. film

Question 56

The units of frequency factor in Arrhenius equation A. are the same as those of the rate constant. B. depend on the order of the reaction. C. depend on temperature, pressure etc. of the reaction. D. are cycles per unit time.

Answer 56

A. are the same as those of the rate constant.

Question 57

Which of the following is not a chemical step in a fluid solid catalytic reaction? A. Surface chemical reaction B. Adsorption C. Desorption D. None of these

Answer 57

D. None of these

Question 58

In case of __________ reactions, the reaction rate does not decrease appreciably as the reaction proceeds. A. catalytic B. parallel C. series D. auto catalytic

Answer 58

D. auto catalytic

Question 59

For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a __________ reactor. A. stirred tank B. tubular flow C. batch D. fixed bed

Answer 59

A. stirred tank

Question 60

B.E.T. method can be used to determine the __________ of a porous catalyst. A. solid density B. pore volume C. surface area D. all (a), (b) and (c)

Answer 60

C. surface area

Question 61

Rate constant for a first order reaction does not depend upon reaction time, extent of reaction and the initial concentration of reactants; but it is a function of reaction temperature. In a chemical reaction, the time required to reduce the concentration of reactant from 100 gm moles/liter to 50 gm moles/liter is same as that required to reduce it from 2 gm moles/liter to 1 gm mole liter in the same volume. Then the order of this reaction is A. 0 B. 1 C. 2 D. 3

Answer 61

B. 1

Question 62

Which of the following is an independent variable for a batch tank reactor with uniform concentration and temperature? A. Time B. Useful volume of the tank C. Diameter of the reactor D. None of these

Answer 62

A. Time

Question 63

For a gaseous phase reaction, rate of reaction is equal to K C_A C_B. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times. A. 8 B. 16 C. 1/8 D. 1/16

Answer 63

B. 16

Question 64

In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants is doubled, then the equilibrium constant will A. remain the same B. be halved C. also be doubled D. become one fourth

Answer 64

A. remain the same

Question 65

The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst. A. increases B. decreases C. remains unaffected D. unpredictable from the data

Answer 65

C. remains unaffected

Question 66

The rate constant of a chemical reaction increases by increasing the A. temperature B. pressure C. reactant's concentration D. none of these

Answer 66

A. temperature

Question 67

The catalytic activity of enzymes is due to their capacity to lower the __________ energy. A. activation B. potential C. kinetic D. none of these

Answer 67

A. activation

Question 68

Pick out the correct statement. A. A lower temperature favors the reaction of lower activation energy. B. The dispersion number for a reactor/vessel is uL/D. C. The rate controlling step in a reaction involving many steps is the fastest step. D. Pore volume and porosity of a catalyst is measured by Brunaver-Emmet-Teller (BET) technique.

Answer 68

A. A lower temperature favors the reaction of lower activation energy.

Question 69

A batch reactor is characterized by A. constant residence time. B. variation in extent of reaction and properties of the reaction mixture with time. C. variation in reactor volume. D. very low conversion.

Answer 69

B. variation in extent of reaction and properties of the reaction mixture with time.

Question 70

When a catalyst increases the rate of forward reaction, the value of rate constant A. increases B. decreases C. remain same D. becomes infinite

Answer 70

A. increases

Question 71

Rate determining step in a reaction consisting of a number of steps in series is the __________ step. A. fastest B. slowest C. intermediate D. data insufficient; can't be predicte

Answer 71

B. slowest

Question 72

The rate of a chemical reaction is almost doubled for every 10°C rise in temperature. The rate will increase __________ times, if the temperature rises from 10 to 100°C. A. 256 B. 512 C. 112 D. 612

Answer 72

B. 512

Question 73

When all the limiting reactant is consumed in the reaction, the operational yield __________ the relative yield. A. is greater than B. is smaller than C. equals D. can be either greater or smaller than (depends on the type of reaction)

Answer 73

C. equals

Question 74

The half life period of a first order reaction is A. always the same irrespective of the reaction. B. dependent on initial concentration of the reactants. C .proportional to the initial concentration of reactants. D .half the specific rate constant.

Answer 74

B. dependent on initial concentration of the reactants.

Question 75

Catalyst carriers A. have very high selectivity. B. increase the activity of a catalyst. C. provide large surface area with a small amount of active material. D. inhibit catalyst poisoning.

Answer 75

C. provide large surface area with a small amount of active material.

Question 76

For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min^-1 . What will be the conversion for a PFR with a space velocity of 0.2 min^-1? Assume that all the other operating conditions are the same for CSTR and PFR. A. 0.15 B. 0.30 C. 0.60 D. 0.90

Answer 76

C. 0.60

Question 77

In flow reactors, the performance equations interrelate the rate of reaction to the A. feed rate. B. reactor volume, C. extent of reaction. D. all (a), (b) and (c).

Answer 77

D. all (a), (b) and (c).

Question 78

Space velocity A. describes the extensive operating characteristics of a tubular flow reactor. B. is the maximum feed rate pre unit volume of reactor for a given conversion. C. is a measure of the ease of the reaction. D. all (a), (b) and (c)

Answer 78

D. all (a), (b) and (c)

Question 79

The rate of the chemical reaction A → B doubles as the concentration of A i.e.., CA is doubled. If rate of reaction is proportional to CA, then what is the value of n for this reaction? A. 0.5 B. 1 C. 0 D. 2

Answer 79

B. 1

Question 80

A reaction which is caalyzed by a base is catalyzed by all substances which have a tendency to A. lose a proton B. gain a proton C. gain an electron D. none of these

Answer 80

C. gain an electron

Question 81

For a homogeneous reaction of nth order, the dimension of the rate constant is given by A. 1/(time)ⁿ B. (concentration)^1-n/(time) C. (concentration)^n-1/(time) D. none of these

Answer 81

B. (concentration)^1-n/(time)

Question 82

The fractional volume change between no conversion and complete conversion, for the isothermal gas phase reaction, 2A → R, is A. 0.5 B. -0.5 C. 1 D. 1.5

Answer 82

B. -0.5

Question 83

The reaction in which one of the products of reaction acts as a catalyst is called a/an __________ reaction. A. biochemical B. photochemical C. catalytic D. autocatalytic

Answer 83

D. autocatalytic

Question 84

A typical example of an exothermic reversible reaction conducted at high pressure in industry is A. dehydration of ethanol. B. methanol synthesis. C. reformation of methane. D. polymerization of ethylene.

Answer 84

A. dehydration of ethanol.

Question 85

Study of chemical kinetics is the easiest in the case of __________ reactions. A. irreversible B. reversible C. surface D. autolysis

Answer 85

A. irreversible

Question 86

In autocatalytic reactions, A. one of the reactants acts as a catalyst. B. one of the products acts as a catalyst. C. catalysts have very high selectivity. D. no catalyst is use

Answer 86

B. one of the products acts as a catalyst.

Question 87

Semi-batch reactor is preferred, when a/an A. a highly exothermic reaction is to be controlled. B. undesirable side reaction (at high concentration of one of the reactants) is to be avoided. C. a gas is to be reacted with liquid (e.g. hydrogenation of fat). D. all (a), (b), and (c).

Answer 87

D. all (a), (b), and (c).

Question 88

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 A. 1 B. >1 C. ∞ D. ≥1

Answer 88

C. ∞

Question 89

What is the order of a chemical reaction whose rate is deter-mined by the variation of one concentration term only? A. zero B. first C. second D. third

Answer 89

B. first

Question 90

Pick out the wrong statement. A. Visible radiation provides the necessary activation energy in photochemical reactions. B. The order and molecularity of a complex reaction may not be the same. C. For a second order reaction, the slope of the graph/plot between rate and (concentration) is equal to the rate constant (k). D. Molecularity of the reaction is always a whole number greater than zero.

Answer 90

B. The order and molecularity of a complex reaction may not be the same.

Question 91

The rate at which a chemical substance reacts is proportional to its A. active mass B. equivalent weight C. molecular weight D. none of these

Answer 91

A. active mass

Question 92

A plug-flow reactor is characterized by A. high capacity. B. presence of axial mixing. C. presence of lateral mixing. D. constant composition and temperature of reaction mixture.

Answer 92

C. presence of lateral mixing.

Question 93

For a tubular reactor with space time 'τ' and residence time 'θ', the following statement holds good. A. τ and θ are always equal. B. τ = θ, when the fluid density changes in the reactor. C. τ = θ, for an isothermic tubular reactor in which the density of the process fluid is constant. D. τ = θ, for a non-isothermal reactor.

Answer 93

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

Question 94

Rate of an autocatalytic chemical reaction is a function of A. temperature only. B. pressure only. C. composition only. D. all (a), (b) and (c).

Answer 94

D. all (a), (b) and (c).

Question 95

Which of the following curves shows the effect of temperature on the extent of gas-solid adsorption at a given pressure? A. Langmuir adsorption isotherm B. Adsorption isobar C. Freundlich adsorption isotherm D. None of these

Answer 95

B. Adsorption isobar

Question 96

Fluid flow in a real packed bed can be approximated as __________ model. A. plug flow B. dispersion C. mixed flow D. tank in series

Answer 96

B. dispersion

Question 97

A reaction which is catalyzed by an acid is also catalyzed by any substance, which has a tendency to A. lose a proton. B. gain a proton. C. lose an electron D. none of these.

Answer 97

A. lose a proton.

Question 98

A stirred tank reactor compared to tubular-flow reactor provides A. more uniform operating conditions. B. permits operation at the optimum temperature for a long reaction time. C. higher overall selectivity for a first order consecutive reaction. D. all (a), (b) and (c)

Answer 98

D. all (a), (b) and (c)

Question 99

In chamber process of sulphuric acid manufacture in industry, the gas phase oxidation of SO2 to SO3 is accomplished by a __________ reaction. A. non-catalytic homogeneous B. non-catalytic heterogeneous C. catalytic homogenous D. catalytic heterogeneous

Answer 99

C. catalytic homogenous

Question 100

If the rate of a chemical reaction becomes slower at a given temperature, then the A. initial concentration of the reactants remains constant. B. free energy of activation is lower. C. entropy changes. D. free energy of activation is higher.

Answer 100

D. free energy of activation is higher.

Question 101

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 ? A. XA Vs τ B. XA Vs ln τ C. XA/(1 - XA) Vs τ D. XA(1 - XA) Vs τ

Answer 101

A. XA Vs τ

Question 102

The rate of the reaction, X → Y, quadruples when the concentration of 'X' is doubled. The rate expression for the reaction is, r = K Cxⁿ, the value of 'n' in this case will be A. 0 B. 1 C. 2 D. 3

Answer 102

C. 2

Question 103

The value of steric factor 'P' in the equation k = PZe^E/RT usually ranges from A. 1.0 to 10^-8 B. 1.1 to 10² C. 0.1 to 0.9 D. none of these

Answer 103

A. 1.0 to 10^-8

Question 104

For a zero order reaction, the concentration of product increases with the A. increase of reaction time. B. increase in initial concentration. C. total pressure. D. decrease in total pressure.

Answer 104

A. increase of reaction time.

Question 105

Pick out the wrong statement. A. 'Hold back' is defined as the fraction of material that stays longer than the mean residence time. B. Study of non-ideal flow reactor is done experimentally by stimulus-response technique. C. For studying a chemical reaction, it is desirable to monitor the reactants during initial stages and the products during the final stages of reaction. D. A batch reactor cannot be used to study the kinetics of catalytic reaction.

Answer 105

D. A batch reactor cannot be used to study the kinetics of catalytic reaction.

Question 106

Effectiveness factor of a catalyst pellet is a measure of the __________ resistance. A. pore diffusion B. gas film C. chemical reaction D. none of these

Answer 106

B. gas film

Question 107

Given, 3H₂ + CO = CH₄ + H₂O, Kp = 10^1.84 4H₂ + CO₂ = CH₄ + 2H₂O, Kp = 10^1.17 The Kp for the reaction CO + H₂O = CO₂ + H₂ is A. 10^3.01 B. 10^-0.67 C. 10^-3.01 D. 10^0.67

Answer 107

D. 10^0.67

Question 108

Differential method for analyzing the kinetic data is used A. for testing complicated mechanisms. B. when the data are scattered. C. when rate expressions are very simple. D. none of these.

Answer 108

A. for testing complicated mechanisms.

Question 109

The reaction in which the rate equation corresponds to a stoichiometric equation is called a/an __________ reaction. A. elementary B. non-elementary C. parallel D. autokinetic

Answer 109

A. elementary

Question 110

The reaction A → B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is A. 0 B. 1 C. 1.5 D. 2

Answer 110

A. 0

Question 111

Arrhenius equation represents graphically the variation between the __________ and temperature. A. rate of reaction B. frequency factor C. rate constant D. activation energy

Answer 111

C. rate constant

Question 112

__________ catalytic reaction is involved in the thermal cracking of gas oil. A. Homogeneous B. Non- Homogeneous C. Heterogeneous D. Non-Heterogeneous

Answer 112

A. Homogeneous

Question 113

Variables affecting the rate of homogeneous reactions are A. pressure and temperature only. B. temperature and composition only. C. pressure and composition only. D. pressure, temperature and composition.

Answer 113

D. pressure, temperature and composition.

Question 114

A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction. A. less than B. equal to C. more than D. equal to or more than

Answer 114

D. equal to or more than

Question 115

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

Answer 115

A. Ash resistance.

Question 116

If the time required to change the concentration of reactant to half its original value is independent of the initial concentration, the order of reaction is A. zero B. one C. two D. three

Answer 116

B. one

Question 117

A batch adiabatic reactor at an initial temperature of 373°K is being used for the reaction, A → B. Assume the heat of reaction is - 1kJ/mole at 373°K and heat capacity of both A and B to be constant and equal to 50 J/mole-K. The temperature rise after a conversion of 0.5 will be A. 5°C B. 10°C C. 20°C D. 100°C

Answer 117

B. 10°C

Question 118

A photochemical reaction is A. accompanied with emission of light. B. catalyzed by light. C. initiated by light. D. all (a), (b) & (c).

Answer 118

C. initiated by light.

Question 119

The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the A. space time for each parallel line is same B. space time for parallel lines is different. C. larger reactors have more space time compared to smaller ones. D. none of these.

Answer 119

A. space time for each parallel line is same

Question 120

Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene: 95 kmole / hr, water vapor: 97.5 k mole / hr and diethyl ether: 2.5 kmole/hr. The reactions occurring can be represented by: C₂H₅OH → C₂H₄ + H₂O 2C₂H₅OH → C₂H₅ - O - C₂H₅ + H₂O The percent conversion of ethanol in the reactor is A. 100 B. 97.5 C. 95 D. 2.5

Answer 120

A. 100

Question 121

A backmix reactor A. is same as plug-flow reactor. B. is same as ideal stirred tank reactor. C. employs mixing in axial direction only. D. is most suitable for gas phase reaction.

Answer 121

B. is same as ideal stirred tank reactor.

Question 122

Rate of a chemical reaction is not influenced by the A. catalyst B. temperature C. reactants concentration D. number of molecules of reactants taking part in a reaction

Answer 122

D. number of molecules of reactants taking part in a reaction

Question 123

Pick out the wrong statement: A. Chemical reactions with high activation energy are very temperature sensitive. B. A flat velocity profile exists in a plug flow reactor. C. The residence time for all the elements of fluid in case of a P.F.R. need not be same. D. Half life of a reaction increases with increased initial concentration for reaction orders more than one.

Question 124

The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m³ is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k)is (Data: Heat of reaction at 298 K = - 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100kJ/kmole. K (may be assumed to be independent of temperature) A. 400 B. 500 C. 600 D. 1000

Answer 124

C. 600

Question 125

In a semi-batch reactor, A. mixing takes place in axial direction only. B. velocity of reaction can be controlled. C. condition similar to plug flow reactor exists. D. residence time is constant.

Answer 125

B. velocity of reaction can be controlled.

Question 126

Which of the following is a controlling factor in very fast heterogeneous reaction? A. Heat and mass transfer effects B. Pressure C. Temperature D. Composition of reactant

Answer 126

A. Heat and mass transfer effects

Question 127

Enzymes are destroyed, when the A. temperature is very high, B. reactant's concentration is very high. C. reactant's concentration is very low. D. reaction rate is independent of the reactant's concentration.

Answer 127

A. temperature is very high,

Question 128

For an autocatalytic reactor, the suitable reactor set up is A. P.F. reactors in series. B. CSTR in series. C. CSTR followed by P.F. reactor. D. P.F. reactor followed by CSTR.

Answer 128

C. CSTR followed by P.F. reactor.

Question 129

Ionic reactions occur in A. solid state only B. liquid state only C. solutions D. any state

Answer 129

C. solutions

Question 130

Half life period of a chemical reaction is A. the time required to reduce the concentration of the reacting substance to half its initial value. B. half of the space time of a reaction. C. half of the residence time of a reaction. D. none of these

Answer 130

A. the time required to reduce the concentration of the reacting substance to half its initial value.

Question 131

In the gaseous phase ammonia formation reaction (N2 + 3H2 → 2NH3), the value of the equilibrium constant depends on the A. total pressure of the system. B. volume of the reactor. C. temperature. D. initial concentration of N2 and H2.

Answer 131

C. temperature.

Question 132

Photochemical reaction rate does not depend significantly on temperature, because A. it is a reversible reaction. B. it is an exothermic reaction. C. the energy of reacting molecules exceeds the activation energy by absorption of light. D. none of these.

Answer 132

C. the energy of reacting molecules exceeds the activation energy by absorption of light.

Question 133

A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type, A → R, is taking place. The reactor is to be provided with a jacket in which coolant is flowing. Following data is given: Cao = 5 kmole/m³; XA = 0.5; Feed temperature = reactor temperature = 40°C. Rate constant at 40°C = 1 min-1; (ΔH) = - 40kJ/mole; ρ = 1000kg/m3 CP = 4 J/gm-°C; q = 10^-3 m²/min (ρ and CP are same for the reactant and product streams). The amount of heat to be removed is A. 2/3 kW B. 1kW C. 5/3 kW D. 4kW

Answer 133

C. 5/3 kW

Question 134

According to the 'law of mass action', the rate of reaction is directly proportional to the A. equilibrium constant. B. volume of the reaction vessel. C. nature of the reactants. D. molar concentration of the reactants.

Answer 134

D. molar concentration of the reactants.

Question 135

For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant A. is independent of pressure. B. increases with pressure. C. decreases with pressure. D. increases /decreases with pressure depending on the stoichiometric coefficients of the reaction.

Answer 135

B. increases with pressure.

Question 136

A batch reactor is A. suitable for gas-phase reactions on commercial scale. B. suitable for liquid phase reactions involving small production rate. C. least expensive to operate for a given rate. D. most suitable for very large production rate.

Answer 136

B. suitable for liquid phase reactions involving small production rate.

Question 137

For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is A. 2 B. 4 C. 11 D. 22

Answer 137

C. 11

Question 138

There is no correspondence between stoichiometry and the rate equation in case of a/an __________ reaction. A. elementary B. multiple C. autocatalytic D. non-elementary

Answer 138

D. non-elementary

Question 139

A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true? A. Inner catalyst core of radius R/8 does not participate in reaction. B. Inner catalyst core of radius R/2 does not participate in reaction. C .Inner catalyst core of radius 7R/8 does not participate in reaction. D. Effectiveness factor for a zero order reaction cannot be 7/8 as it must always be 1.

Answer 139

A. Inner catalyst core of radius R/8 does not participate in reaction.

Question 140

Which of the following is used for calcination of limestone and dolomite in industrial practice? A. Fluidized bed reactor B. Moving bed reactor C. Fixed bed reactor D. None of these

Answer 140

B. Moving bed reactor

Question 141

An imbalanced chemical reaction equation is against the law of A. multiple proportion B. conservation of mass C. constant proportion D. none of these

Answer 141

B. conservation of mass

Question 142

Which of the following is a characteristic of an ideal plug flow reactor? A. Axial dispersion B. Flat velocity profile C. Uniform mixing D. None of these

Answer 142

B. Flat velocity profile

Question 143

An isothermal aqueous phase reversible reaction, P ⇔ R, is to be carried out in a mixed flow reactor. The reaction rate in kmole/m³-h is given by, r = 0.5C_P - 0.125C_R. A stream containing only P enters the reactor. The residence time required (in hours) for 40% conversion of P is A. 0.80 B. 1.33 C. 1.60 D. 2.67

Answer 143

C. 1.60

Question 145

What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on? A. Liter/mole-second B. Moles/liter-second C. Liter/mole D. Liter/second

Answer 145

A. Liter/mole-second

Question 146

For a fluidized bed reactor, the most suitable/relevant model is a __________ model. A. tank in series B. bubbling bed C. plug flow D. none of these

Answer 146

B. bubbling bed

Question 147

The rate at which a chemical substance reacts is proportional to its A. active mass B. molecular weight C. equivalent weight D. atomic weight

Answer 147

A. active mass

Question 148

The most suitable reactor for carrying out an auto-thermal reaction is a A. batch reactor B. CSTR C. semi-batch reactor D. plug-flow reactor

Answer 148

B. CSTR

Question 149

Limiting reactant in a chemical reaction decides the A. rate constant B. conversion C. reaction speed D. equilibrium constant

Answer 149

B. conversion

Question 150

In case of a consecutive unimolecular type first order reaction , the concentration of component __________ increases continuously with time. A. S B. R C. A D. none of these

Answer 150

A. S

Question 151

The exit age distribution of fluid leaving a vessel is used to know the A. activation energies of a reaction. B. reaction mechanism. C. extent of non-ideal flow in the vessel. D. none of these.

Answer 151

C. extent of non-ideal flow in the vessel.

Question 152

From Arhenius law, a plot of loge K versus 1/T gives a straight line with a slope of (-E/R). The unit of E/R is A. k cal B. k cal/°K C. °K D. k cal. °K

Answer 152

C. °K

Question 153

Reverse reaction in a chemical equilibrium is favoured by the A. removal of one of the products regularly. B. increase in the concentration of one of the products. C. increase in the concentration of one of the reactants. D. none of these.

Answer 153

B. increase in the concentration of one of the products.

Question 154

Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction. A. order B. overall order C. molecularity D. none of these

Answer 154

B. overall order

Question 155

During manufacture of H₂SO₂, the oxidation of SO₂ to SO₃ by oxygen is an endothermic reaction. The yield of SO₃ will be maximised, if the A. temperature is increased. B. pressure is reduced. C. temperature is increased and pressure is reduced. D. temperature is reduced pressure is increased.

Answer 155

D. temperature is reduced pressure is increased.

Question 156

BET apparatus is used to determine the A. specific surface of a porous catalyst. B. pore size distribution. C. pore diameter. D. porosity of the catalyst bed.

Answer 156

A. specific surface of a porous catalyst.

Question 157

When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value. A. twice B. half C. equal D. none of thes

Answer 157

B. half

Question 158

Kinetics of a solid catalysed reaction can best be studied in a __________ reactor. A. batch B. plug-flow C. mixed D. none of these

Answer 158

C. mixed

Question 159

The reactions of high molecularity are rare, because A. of very large activation energy of many bodies. B. of low probability of many body collisions. C. many body collisions are not favoured energetically. D. of requirement of very large concentration for such reactions.

Answer 159

B. of low probability of many body collisions.

Question 160

Which of the following is the most suitable for isothermal operation ? A. Batch reactor B. Back-mix reactor C. Plug-flow reactor D. Fixed bed reactor

Answer 160

B. Back-mix reactor

Question 161

For a first order chemical reaction, the rate constant A. changes on changing the concentration units. B. is not a function of the unit of time. C. has unit of time^-1 D. none of these

Answer 161

C. has unit of time^-1

Question 162

Which of the following is an autocatalytic reaction ? A. Photochemical reactions B. Microbial fermentation reaction C. Enzyme fermentation reaction D. Ammonia synthesis reaction

Answer 162

B. Microbial fermentation reaction

Question 163

Oil is hydrogenated using nickel catalyst in a __________ reactor. a. batch b. slurry c. fluidised bed d. fixed bed

Answer 163

b. slurry

Question 164

The performance equations for constant density systems are identical for a. P.F.R. and backmix reactor. b. P.F.R. and batch reactor. c. P.F.R, batch reactor and backmix reactor. d. batch reactor and backmix reactor.

Answer 164

b. P.F.R. and batch reactor.

Question 165

Reaction rate of a first order reaction, which is half completed in 23 minutes will be a. 0.03 sec^-1 b. 0.03 min^-1 c. 0.03 hr^-1 d. 0.05 min^-1

Answer 165

b. 0.03 min^-1

Question 166

Which of the following is the optimum operating condition for an exothermic reversible reaction taking place in a plug-flow reactor? a. Temperature should be high in the beginning and decreased towards the end of the reaction. b. Very low temperature should be used throughout the reaction. c. Very high temperature should be used throughout the reaction. d. none of these.

Answer 166

a. Temperature should be high in the beginning and decreased towards the end of the reaction.

Question 167

Promoter is added to the catalyst to improve its a. porosity b. sensitivity c. surface area d none of these

Answer 167

b. sensitivity

Question 168

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 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.

Answer 168

b. be more in PFR than in CSTR.

Question 169

When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ column. a. packed b. spray c. tray d. bubble

Answer 169

d. bubble

Question 170

For a tubular flow reactor with uniform concentration and temperature, the independent variable is a. time b. length c. diameter d. none of these

Answer 170

b. length

Question 171

The reactions with low activation energy are a. always spontaneous b. slow c. fast d. non-spontaneous

Answer 171

c. fast

Question 172

Which of the following is not endothermic in nature ? a. Combustion of sulphur. b. Gasification of carbon. c. Thermal cracking of fuel oil. d. Steam reforming of naphtha.

Answer 172

a. Combustion of sulphur.

Question 173

The space time is equivalent to the holding time in a steady state mixed reactor for a. non-isothermal gas reaction. b. variable fluid density systems. c. constant fluid density systems. d. gas reactions with changing no. of moles.

Answer 173

c. constant fluid density systems.

Question 174

The dispersion number of perfect mixed flow is a. 0 b. > 150 c. ∞ d. < 2100

Answer 174

c. ∞

Question 175

An irreversible aqueous phase reaction, A + B → P, is carried out in an adiabatic mixed flow reactor. A feed containing 4kmole/m³ of each A and B enters the reactor at 8 m²/hr. If the temperature of the exit stream is never to exceed 390 K, what is the maximum inlet feed temperature allowed? Data: Heat of reaction = - 50 kJ/mole Density of the reacting mixture = 1000 kg/m³ Specific heat of reacting mixture = 2 kJ/kg-K The above data can be assumed to be independent of temperature and composition. a. 190 b. 290 c. 390 d. 490

Answer 175

b. 290

Question 176

Half life period of a first order irreversible reaction A → B is a. k/2 b. ln k/2 c. ln 2/k d. ln 0.5/k

Answer 176

c. ln 2/k

Question 177

Half life period of decomposition of a liquid 'A' by irreversible first order reaction is 12 minutes. The time required for 75% conversion of 'A' is __________ minutes. a.18 b. 24 c. 6 d. 12

Answer 177

b. 24

Question 178

With increase in the space time of an irreversible isothermal reaction being carried out in a P.F. reactor, the conversion will a. increase b. decrease c. remain same d. data in insufficient; can't be predicted

Answer 178

a. increase

Question 179

If ΔG (free energy change) for a chemical reaction is very large and negative, then the reaction is a. not feasible. b. just feasible. c. very much feasible. d. unpredictable as ΔG is no measure of feasibility of a reaction.

Answer 179

c. very much feasible.

Question 180

In a zero order reaction, reactants concentration does not change with time and the a. time for half change is half the time taken for completion of the reaction. b. time for half change is independent of the initial concentration. c. time for completion of the reaction is independent of the initial concentration. d. reaction rate is trebled when the initial concentration is trebled.

Answer 180

a. time for half change is half the time taken for completion of the reaction.

Question 181

The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reaction with low activation energy are a. always irreversible. b. insensitive to temperature changes. c. mostly irreversible d. highly temperature sensitivr

Answer 181

b. insensitive to temperature changes.

Question 182

If Thiele modulus is __________ , then the pore diffusion resistance in a catalyst may be considered as negligible. a. 0 b. ∞ c. < 0.5 d. 0.5

Answer 182

c. < 0.5

Question 183

Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the a. activation energy b. equilibrium constant c. heat of reaction d. none of these

Answer 183

a. activation energy

Question 184

In Langmuir treatment of adsorption, a. whole surface of the catalyst does not have the same activity for adsorption and there is attraction between the adsorbed molecule. b. whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect on the rate of adsorption per site. c. all the adsorption does not take place by the same mechanism. d. extent of adsorption is more than one complete monomolecular layer on the surface.

Answer 184

b. whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect on the rate of adsorption per site.

Question 185

Organic catalysts differ from the inorganic catalyst in the sense that the former is a. active at cryogenic temperatures only. b. prohibitively costly. c. proteinous in nature. d. active at very high temperature only.

Answer 185

c. proteinous in nature.

Question 186

An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction a. is maximum at the inlet of the reactor. b. goes through a maximum along the length of the reactor. c. goes through a minimum along the length of the reactor. d. is maximum at the exit of the reactor.

Answer 186

a. is maximum at the inlet of the reactor.

Question 187

For an ideal plug flow reactor, the value of Peclet number is a. 0 b. ∞ c. 1 d. 10

Answer 187

a. 0

Question 188

An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation i a. maximum at the inlet of the reactor. b. maximum at the exit of the reactor. c. maximum at the centre of the reactor. d. constant throughout the reactor.

Question 189

Equilibrium of a chemical reaction as viewed by kinetics is a __________ state. a. dynamic steady b. static steady c. dynamic unsteady d. none of these

Answer 189

a. dynamic steady

Question 190

The conversion in a mixed reactor/accomplishing a reaction A → 3R is 50% when gaseous reactant 'A' is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is __________ second. a. 0.5 b. 1 c. 2 d. 3

Answer 190

a. 0.5

Question 191

The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is __________ that of mixed reactor. a. greater than b. equal to c. smaller than d. unpredictable from the data

Answer 191

c. smaller than

Question 192

A space time of 3 hours for a flow reactor means that a. the time required to process one reactor volume of feed (measured at specified conditions) is 3 hours. b. three reactor volumes of feed can be processed every hour. c. it takes three hours to dump the entire volume of the reactor with feed. d. conversion is cent per cent after three hours.

Answer 192

a. the time required to process one reactor volume of feed (measured at specified conditions) is 3 hours.

Question 193

If the time required for half change is inversely proportional to the square of initial concentration and the velocity depends on the units in which the concentration term is expressed, then the order of reaction is a. 1 b. 2 c. 3 d. 0

Answer 193

c. 3

Question 194

In a continuous flow stirred tank reactor, the composition of the exit stream a. is same as that in the reactor. b. is different than that in the reactor. c. depends upon the flow rate of inlet stream. d. none of these.

Answer 194

a. is same as that in the reactor.

Question 195

The energy balance equation over a tubular reactor under transient conditions is a. an ordinary non-linear differential equation. b. an algebraic differential equation. c. a linear partial differential equation. d. a non-linear partial differential equation.

Answer 195

c. a linear partial differential equation.

Question 196

Maximum equilibrium conversion for endothermic reaction is obtained at the __________ temperature. a. highest possible b. lowest possible c. intermediate d. room

Answer 196

a. highest possible

Question 198

For a first order chemical reaction in a porous catalyst, the Thiele modulus is 10. The effectiveness factor is approximately equal to a. 1 b. 0.5 c. 0.1 d. 0

Answer 198

c. 0.1

Question 199

In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for a. fast reactions in catalyst of small pore diameter. b. fast reaction in catalyst of large pore diameter. c. slow reactions in catalyst of small pore diameter. d. slow reactions in catalyst of large pore diameter.

Answer 199

c. slow reactions in catalyst of small pore diameter.

Question 200

Helium-mercury method can be used to determine the __________ of the catalyst particle. a. pore volume b. solid density c. porosity d. all (a), (b), & (c).

Answer 200

d. all (a), (b), & (c).

Question 201

In a semi-batch reactor a. velocity of reaction can be controlled. b. maximum conversion can be controlled. c. both the reactants flow counter-currently. d. residence time is constant.

Answer 201

a. velocity of reaction can be controlled.

Question 202

A trickle bed reactor is the one, which a. has altogether three streams either entering or leaving. b. processes three reactants at different flow rates. c. processes three reactants with same flow rate. d. employs all the three phases (i.e.. .solid, liquid and gas).

Answer 202

d. employs all the three phases (i.e.. .solid, liquid and gas).

Question 203

What is the order of a chemical reaction in which doubling the initial concentration of the reactants doubles the half lifetime of the reaction? a. 0 b. 1 c. 2 d. 3

Answer 203

a. 0

Question 204

In a/an __________ vessel, the fluid enters and leaves following plug flow. a. open b. closed c. open-closed d. close-opened

Answer 204

b. closed

Question 205

Shift conversion reaction a. converts N2 and H2 into NH3. b. converts CO to CO2 with steam. c. is non-catalytic. d. is highly exothermic.

Answer 205

b. converts CO to CO2 with steam.

Question 206

Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature? a. Pore diffusion b. Film diffusion c. Ash layer diffusion d. Chemical reaction

Answer 206

b. Film diffusion

Question 207

The ratio of moles of a reactant converted into the desired product to that converted into unwanted product is called a. operational yield b. relative yield c. selectivity d. none of these

Question 208

The response curve for a step input signal from a reactor is called C-curve. The variance of C-curve in a 'tanks in series model' comprising of 'm' tanks is equal to a. m b. 1/m c. m d. m²

Answer 208

b. 1/m

Question 209

The eddy diffusivity for a liquid in plug flow must be a. 1 b. 0 c. ∞ d. between 0 and 1

Answer 209

b. 0

Question 210

For the same residence time, which one will give the maximum conversion? a. Single stirred tank (v = 5 litres). b. Two stirred tank (each of 2.5 litres) in series. c. Stirred tank followed by tubular flow reactor (each of 2.5 litres). d. Single tubular flow reactor (v = 5 litres).

Answer 210

d. Single tubular flow reactor (v = 5 litres).

Question 211

The rate constant of a reaction depends on the a. Initial concentration of reactants. b. Time of reaction. c. Temperature of the system. d. Extent of reaction

Answer 211

c. Temperature of the system.

Question 212

For the reversible reaction A 2B, if the equilibrium constant K is 0.05 mole litre; starting from initially 2 moles of A and zero moles of B, how many moles will be formed at equilibrium? a. 0.253 b. 0.338 c. 0.152 d. 0.637

Answer 212

b. 0.338

Question 213

For identical flow rate and feed composition, X plug flow reactors (PER) in series with a total volume V gives the same conversion as single a. CSTR of volume b. PFR of volume V c. CSTR of volume V/X d. PFR of volume V/X

Answer 213

b. PFR of volume V

Question 214

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. a. 3 b. 4 c. 6 d. 8

Answer 214

b. 4

Question 215

For a __________ order reaction, the units of rate constant and rate of reaction are the same. a. Zero b. First c. Second d. Fractional

Answer 215

a. Zero

Question 216

Vegetable oils are hydrogenated in a __________ reactor. a. slurry b. plug flow c. homogeneous catalytic d. none of these

Answer 216

a. slurry

Question 217

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 a. 1/2 b. 1/3 c. 1/4 d. 1/5

Answer 217

b. 1/3

Question 218

The rate of reaction does not decrease appreciably as the reaction proceeds in case of __________ reactions. a. autocatalytic b. exothermic c. endothermic d. autothermal

Answer 218

a. autocatalytic

Question 219

The heat of reaction 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.

Answer 219

d. Is independent of the mechanism of reaction.

Question 220

Which of the following does not produce a change in the value of rate constant of a reaction ? a. Pressure b. Temperature c. Concentration and catalyst d. None of these.

Answer 220

c. Concentration and catalyst

Question 221

With increase in temperature, the equilibrium conversion of a reversible exothermic reaction a. decreases b. increase c. remains unaffected d. decreases linearily with temperature

Answer 221

a. decreases

Question 222

Photo-chemical reactions occur in presence of a. sunlight. b. darkness, c. solid catalysts. d. monochromatic radiation only.

Answer 222

a. sunlight.

Question 223

Knudsen diffusion is directly proportional to a. T b. √T c. 1/T d. T²

Answer 223

b. √T

Question 224

Fractional conversion __________ for an exothermic reversible chemical reaction, when the temperature is maximum. a. increases b. remains unchanged c. decreases d. unpredictable from the data

Answer 224

c. decreases

Question 225

A pulse tracer is introduced in an ideal CSTR (with a mean residence time (t) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be a. 2τ b. 0.5τ c. τ/0.693 d. 0.693τ

Answer 225

a. 2τ

Question 226

On application of pressure to the equilibrium system, ice water ; which of the following phenomenon will occur? a. Water will evaporate b. Equilibrium will not be attained c. More ice will be formed d. More water will be formed.

Answer 226

d. More water will be formed.

Question 227

Participation of __________ is involved in the occurrence of a chemical reaction. a. protons b. neutrons c. electrons d. none of these

Answer 227

c. electrons

Question 228

The value of 'n' for a chemical reaction A B, whose reaction rate is CAn, will be __________ if the rate of the reaction increases by a factor of 8, when the concentration of is doubled. a. 0 b. 1 c. 2 d. 3

Answer 228

d. 3

Question 229

With the same reaction time, initial concentration and feed rate, the reaction 2A B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be a. higher in P.F. reactor b. higher in CSTR c. same in both the reactors d. data insufficient; can't be predicted

Answer 229

a. higher in P.F. reactor

Question 230

The use of space time is preferred over the mean residence time in the design of a/an a. batch reactor b. ideal tubular-flow reactor c. slurry reactor d. CSTR

Answer 230

b. ideal tubular-flow reactor

Question 231

Autocatalytic reactions are best carried out in a a. CSTR b. CSTR in series c. plug flow reactor d. recycle reactor

Answer 231

d. recycle reactor

Question 232

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/Cao at the outlet of the reactor is a. 2/3 b. 5/8 c. 1/3 d. 3/8

Answer 232

b. 5/8

Question 233

A first order reaction is to be treated in a series of two mixed reactors. The total volume of the two reactors is minimum, when the reactors are a. Equal in size. b. of different sizes. c. of such size that the ratio of their volumes is < 5. d. none of these.

Answer 233

a. Equal in size.

Question 234

The equilibrium constant K of a chemical reaction depends on a. temperature only. b. pressure only. c. temperature and pressure. d. ratio of reactants.

Answer 234

a. temperature only.

Question 235

The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the a. increased temperature reduces the activation energy. b. fraction of molecules having threshold energy increases. c. collision frequency increases. d. value of threshold energy decreases.

Answer 235

b. fraction of molecules having threshold energy increases.

Question 236

The synthesis of proteins and metabolism in biological objects occur in the presence of biocatalyst called a. a ferment or an enzyme b. haemoglobin c. fungi d. none of these

Answer 236

c. fungi

Question 237

In case of a __________ reactor, the composition in the reactor and at the exit of the reactor is the same. a. semi-batch b. tubular c. batch d. back-mix

Answer 237

d. back-mix

Question 238

Exothermic reactions are best carried out in a. a CSTR. b. CSTR in series. c. a plug flow reactor followed by CSTR. d. CSTR followed by a plug flow reactor.

Answer 238

d. CSTR followed by a plug flow reactor.

Question 239

Reactions with high activation energy are a. very temperature sensitive b. temperature insensitive c. always irreversible d. always reversible

Answer 239

a. very temperature sensitive

Question 240

A space velocity of 5 hr^-1 means that a. five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour. b. after every 5 hours, reactor is being filled with the feed. c. cent per cent conversion can be achieved in at least 5 hours. d. a fixed conversion of a given batch of feed takes 5 hours.

Answer 240

a. five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour.

Question 241

Half-life period for a first order reaction is __________ the initial concentration of the reactant. a. directly proportional to b. inversely proportional to c. independent of d. none of these

Answer 241

c. independent of

Question 242

A gaseous reactant is introduced in a mixed reactor of 3 litres volume at the rate of 1 litre/second. The space time is __________ seconds. a. 1 b. 3 c. 1/3 d. 32

Answer 242

b. 3

Question 243

Fluidized bed reactor is characterised by a. uniformity of temperature b. comparatively smaller equipment. c. very small pressure drop. d. absence of continuous catalyst regeneration facility.

Answer 243

a. uniformity of temperature

Question 244

Space time equals the mean residence time a. when the density of the reaction mixture is constant. b. for large diameter tubular reactor. c. for narrow diameter tubular reactor. d. for CSTR.

Answer 244

a. when the density of the reaction mixture is constant.

Question 245

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. a. 4 b. 8 c. 12 d. 16

Answer 245

d. 16

Question 246

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 a. 60 b. 75 c. 90 d. 100

Answer 246

b. 75

Question 247

What is the dispersion number for a CSTR?. a. 0 b. 1 c. < 1 d. ∞

Answer 247

d. ∞

Question 248

Rate of a chemical reaction is independent of the concentration of the reactants for a __________ reaction. a. zero order b. third order c. consecutive d. none of these

Answer 248

a. zero order

Question 249

Bulk diffusion in catalyst pore __________ with increase in pressure. a. increases b. decreases c. remains unchanged d. increases exponentially

Answer 249

a. increases

Question 250

A second order reaction of the form A + B → C is called a pseudo-first order reaction, when a. Cao = Cbo b. Cao > Cbo c. Cbo > Cao d. Cbo ≥ Cbo

Answer 250

d. Cbo ≥ Cbo