Chemical Reaction Engineering MCQ (Multiple Choice Questions)

Here are 1000 MCQs on Chemical Reaction Engineering (Chapterwise).

1. What is the chemical reaction rate?
a) Chemical reaction rate is a chemical property
b) Chemical reaction rate is a physical property
c) Chemical reaction rate is an intensive property
d) Chemical reaction rate is an extensive property
View Answer

Answer: c
Explanation: Chemical reaction rate depends on temperature and concentration. Hence, it is an intensive property.

2. Which of the following deals with the study of rates at which chemical reactions occur and the effect of various parameters on the rate?
a) Fluid Mechanics
b) Chemical Technology
c) Chemical Sciences
d) Chemical Kinetics
View Answer

Answer: d
Explanation: Chemical Kinetics is the study of the rate of a chemical reaction and the effect of parameters like temperature, pressure, concentration, etc. on reaction rates. Kinetic studies help in obtaining information about reaction mechanisms and transition states.

3. If \(\frac{τ}{t}=\frac{1}{3},\) average conversion for a particle B of constant size in a mixed flow reactor for chemical reaction controlling is?
a) 0.75
b) 0.92
c) 0.76
d) 0.98
View Answer

Answer: b
Explanation: \(\overline{X_{(B)}} = 3(\frac{\overline{t}}{τ}) -6 (\frac{\overline{t}}{τ})^2+ 6(\frac{\overline{t}}{τ})^3(1-e^\frac{τ}{\overline{t}}, 1-\overline{X_{(B)}}\) = 0.078 and \(\overline{X_{(B)}}\) = 0.92

4. Catalyst is a substance that ___________
a) Can either increase or decrease the speed of a chemical reaction
b) Alters the value of the equilibrium constant in a reversible chemical reaction
c) Increases the speed of a chemical reaction
d) Decreases the speed of a chemical reaction
View Answer

Answer: a
Explanation: Catalyst is a substance that increases the speed of reaction without consuming itself at the end of the reaction, and the phenomenon is called catalysis. There are some catalysts that decrease the speed of reaction and these catalysts are called negative catalysts.

5. For the mixed flow of particles containing a single unchanging size and uniform gas composition, the fraction unconverted for chemical reaction controlling is?
a) \(\int_0^τ\)(1-\(\frac{t}{τ}\))0.5\(\frac{e}{t}^\frac{-t}{t}\) dt
b) \(\int_0^τ\)(1-\(\frac{t}{τ}\))\(\frac{e}{t}^\frac{-t}{t}\) dt
c) \(\int_0^τ\)(1-\(\frac{t}{τ}\))2\(\frac{e}{t}^\frac{-t}{t}\) dt
d) \(\int_0^τ\)(1-\(\frac{t}{τ}\))3\(\frac{e}{t}^\frac{-t}{t}\) dt
View Answer

Answer: d
Explanation: For chemical reaction controlling, \(\frac{t}{τ}\) = 1-(1- XB)\(^\frac{1}{3}\). Hence, 1-\(\overline{X_{(B)}}\) = ∫0τ(1-\(\frac{t}{τ}\))3\(\frac{e}{t}^\frac{-t}{t}\) dt.
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6. Which of the following is true for fluidized catalytic beds?
a) There is no pressure drop
b) They come under the category of batch reactors
c) The bulk density is a function of the flow rate through the bed
d) They cannot be used for multi-phase chemical reactions
View Answer

Answer: c
Explanation: Fluidized catalytic beds are mostly used for multi-phase reactions, for example, cumene decomposition. They come underflow reactors. The inclusion of a fluidized bed offers more resistance to flow and hence results in a pressure drop.

7. In which of the following reaction the rate of reaction is a function of rate constant alone is?
a) Zero order reaction
b) Third order reaction
c) First order reaction
d) Second order reaction
View Answer

Answer: a
Explanation: Zero order reaction is the one in which rate does not depend on concentration.
(-r) = k
k → Rate constant

8. Which of the following represents heterogeneous catalytic reaction?
a) Reduction of iron ore
b) Ammonia synthesis
c) Burning of coal
d) Roasting of ores
View Answer

Answer: b
Explanation: Ammonia synthesis is a heterogeneous reaction. Iron is used as a catalyst in the synthesis of ammonia by Haber’s process.

9. If rate of a zero order reaction is 10 \(\frac{mol}{m^3×s}\) and reaction time is 5s, then the value of rate constant is ____
a) 2 s-1
b) 5 s-1
c) 10 s-1
d) 1 s-1
View Answer

Answer: a
Explanation: (-rA) = kCAn
10 = k (5)
Hence, k = 2 s-1.

10. Which of the following is the most suitable reactor for the pharmaceutical industry?
a) PBR
b) MFR
c) PFR
d) Batch reactor
View Answer

Answer: d
Explanation: When small-scale production is desired, high or stringent quality standards to be met batch reactors used extensively.

11. If the conversion of a first-order liquid phase reaction occurring in a CSTR is 75%, molar feed rate is 5 mol/min, the rate of the reaction is 5 \(\frac{mol}{litre.min} \) then the volume of the reactor (in litre) is?
a) 0.33
b) 0.4
c) 0.75
d) 0.5
View Answer

Answer: c
Explanation: For a CSTR, the performance equation is FA0XA = (-rA)V
FA0 is molar feed rate and XA is the fractional conversion
5 × 0.75 = 5 × V
V = 0.75 L

12. The rate constant of a first order reaction depends on the _____________
a) Temperature
b) Concentration
c) Time
d) Pressure
View Answer

Answer: a
Explanation: The reaction rate constant depends on temperature only.

13. Which of the following is an example of autocatalytic reaction?
a) Oxidation of copper
b) Ammonia formation reaction
c) Hydrogen peroxide decomposition reaction
d) Reaction of permanganate with oxalic acid
View Answer

Answer: d
Explanation: Permanganate in acidic medium oxidises the oxalic acid. This reaction produces Mn2+ ions, which in turn catalyses the reaction.

14. Which of the following reactor arrangements causes fast deactivation?
a) Fluidised bed reactor
b) Batch for fluid and solid
c) Plug flow for fluid
d) Mixed flow for fluid
View Answer

Answer: a
Explanation: Fluidisation causes high catalytic deactivation. The catalytic particles are well mixed by the reactant fluid.
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15. Which of the following is not a reversible reaction?
a) Oxidation of sulphur dioxide to sulphur trioxide
b) Ammonia formation from its elements
c) Formation of hydrogen bromide from its elements
d) Decomposition reaction of nitrogen pentoxide
View Answer

Answer: c
Explanation: The reaction of hydrogen with bromine is irreversible reaction. H2 + Br2 → HBr.

16. If τ = 5 s, first order rate constant, k = 0.25 sec-1 and the number of tanks, N is 5, then the conversion is?
a) 87.45%
b) 33%
c) 75%
d) 67.2%
View Answer

Answer: d
Explanation: XA = 1-\(\frac{1}{(1+\frac{τk}{N})^N} \)
1-\(\frac{1}{(1+\frac{5×0.25}{5})^5}\) = 67.2%.

17. The catalyst in a first-order chemical reaction changes the _______________
a) Activation energy
b) Equilibrium constant
c) Heat of reaction
d) Heat of formation of the product
View Answer

Answer: a
Explanation: A catalyst in a first-order chemical reaction changes the Activation energy.

18. Which of the following is the correct expression for the rate of a reaction?
a) \(\frac{Moles \, unreacted}{Volume \, of \, fluid×Time} \)
b) \(\frac{Moles \, of \, product \, formed}{Volume \, of \, fluid} \)
c) \(\frac{Moles \, of \, product \, formed}{Volume \, of \, fluid×Time} \)
d) \(\frac{Moles \, of \, reactant \, initially \, taken}{Volume \, of \, fluid×Time} \)
View Answer

Answer: c
Explanation: Rate of the reaction is the number of moles of the reactant component disappearing per unit volume per unit time. The moles of the product formed are the number of moles of the reactant species disappearing during the course of reaction.

19. The rate of reaction is rapid for which of the following reactions?
a) Gas reactions in porous catalysts
b) Reactions in rocket engines
c) Cellular reactions
d) Reactions in coal furnaces
View Answer

Answer: b
Explanation: The rate of reaction in rocket engines is in the range 105-108. The order of decrease in rates is, Reactions in rocket engines > Reactions in coal furnaces > Gas reactions in porous catalysts > Cellular reactions.
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20. Which of the following is an isomerization reaction?
a) Conversion of glucose to fructose
b) Combustion reactions
c) Formation of ammonia from hydrogen and nitrogen
d) Decomposition of hydrogen peroxide to hydrogen and oxygen
View Answer

Answer: a
Explanation: Isomerisation is the process in which one molecule gets transformed into another molecule that has absolutely the same atoms which are arranged in a different way. Glucose and fructose, share the same molecular formula: C6H12O6. Although all they have the same molecular formula, the arrangement of atoms differs.

21. Which of the following theories does not propose the temperature dependence of rate constant?
a) Transition state theory
b) Bohr’s theory
c) Arrhenius theory
d) Collision theory
View Answer

Answer: b
Explanation: Bohr’s theory proposes the model of an atom. Arrhenius theory, Collision theory, Transition state theory propose the variation of rate constant with temperature.

22. What is the unit of activation energy?
a) J/ mol
b) K
c) mol
d) mol.K
View Answer

Answer: a
Explanation: Activation energy is expressed in J/ mol or kJ/ mol. Activation energy is the energy required for a chemical reaction to occur.

23. Which of the following is true for gas-phase reactions?
a) Decrease in moles of the product increases the volume of the reaction mixture
b) Increase in moles of the product does not affect the volume of the reaction mixture
c) Increase in moles of the product increases the volume of the reaction mixture
d) Increase in moles of the product decreases the volume of the reaction mixture
View Answer

Answer: c
Explanation: Increase in moles of product increases reaction mixture volume. For a reaction proceeding such that the moles of products are higher than moles of reactants, the volume of the reaction mixture increases.

24. Which of the following is NOT a part of reactor design?
a) Flow rates of the reactant and product streams
b) Method of operation
c) Type of the reactor
d) Size of the reactor
View Answer

Answer: a
Explanation: In general, most reactors are not stand-alone units. They are part of huge plants. This means that the flow rates of reactant and/or product streams depend on a lot of factors and may even be pre-decided. The purpose of reactor design, therefore, is to determine the reactor size and type and the suitable method of operation to meet the flow rate or other requirements.

25. Which of the following reactions follows elementary rate law?
a) Reversible catalytic decomposition of isopropyl benzene
b) Formation of hydrogen bromide
c) Vapor phase decomposition of ethanol
d) Cis-trans isomerization
View Answer

Answer: d
Explanation: Cis-trans isomerization follows elementary rate laws. Hydrogen bromide formation reaction, as well as the reversible catalytic decomposition of isopropyl benzene, are non-elementary in nature. Rate of vapor phase decomposition of ethanal is proportional to Cethanal3/2.

26. Which of the following is true for the rate law of a reversible reaction?
a) Rate law can be written only in terms of concentrations
b) It reduces to irreversible form when product concentration is zero
c) It satisfies thermodynamic relationships at all times
d) Rate law can be written only in terms of partial pressures
View Answer

Answer: b
Explanation: Rate law can be written in terms of both concentrations or partial pressures. The thermodynamic relationships are satisfied only at equilibrium. If the product concentration is zero, the rate of the backward reaction becomes zero and the rate law reduces to irreversible form.

27. Which of the following constants is a type of equilibrium constant?
a) Association constant
b) Solubility
c) Decay constant
d) Dissociation constant
View Answer

Answer: c
Explanation: Decay constant is actually a type of rate constant, for a given decay reaction. Solubility, association and dissociation constants are equilibrium constants. These are reaction quotients calculated at the stag of ionic equilibrium w.r.t various ionic and non-ionic species present in a system.

28. Which of the following represents series type deactivation model? (Where R is the product and P is the poison)
a) A → R + P↓
b) A → R → P↓
c) A → R, A → P
d) A → P↓
View Answer

Answer: b
Explanation: The series deactivation is the mechanism in which the product may decompose to produce the poison or further react to produce the poison. The poison deposits on the catalyst and causes deactivation.

29. What is the activity of a catalyst when a time t = 0?
a) Unity
b) ∞
c) Zero
d) Negative
View Answer

Answer: a
Explanation: When the reaction has not yet started to occur, the catalyst surface is not poisoned. The entire surface on the catalyst is available to promote the reaction. At a time t=0, the activity is the highest and equal to 1. The value of ‘a’ lies between 0 and 1 as ‘a’ is the ratio of the rate of reaction achieved by the catalyst at any given time to the maximum rate that can be achieved by a fresh catalyst.

30. Which of the following represents second-order bimolecular type reversible reaction?
a) A+B ↔ R
b) A ↔ R+S
c) A ↔ B
d) A+B ↔ R+S
View Answer

Answer: d
Explanation: Bimolecular reaction involves 2 molecules. Both reactants and products react simultaneously.

31. Which of the following is not a characteristic of tracer?
a) Easily detectable
b) Absorbance onto the reactor surface
c) Inertness
d) Non-reactive
View Answer

Answer: b
Explanation: The tracer should not stick to the walls or other surfaces of the reactor. The physical properties of the tracer should be similar to that of the system.


Chapterwise Multiple Choice Questions on Chemical Reaction Engineering

Chemical Reaction Engineering MCQ - Multiple Choice Questions and Answers

Our 1000+ MCQs focus on all topics of the Chemical Reaction Engineering subject, covering 100+ topics. This will help you to prepare for exams, contests, online tests, quizzes, viva-voce, interviews, and certifications. You can practice these MCQs chapter by chapter starting from the 1st chapter or you can jump to any chapter of your choice.
  1. Chemical Reaction Engineering Basic Concepts
  2. Elements of Reaction Kinetics
  3. Kinetics of Homogeneous Reactions
  4. Homogenous Reactions in Ideal Reactors
  5. Ideal Reactors for a Single Reaction, Conversion and Reactor Sizing
  6. Rate Laws and Stoichiometry
  7. Isothermal Reactor Design
  8. Collection and Analysis of Rate Data
  9. Potpourri of Multiple Reactions
  10. Solid Catalysed Reactions
  11. Fluid-Particle Reactions: Kinetics
  12. Packed Bed Catalytic Reactor
  13. Catalyst Deactivation
  14. Distribution of Residence Time for Chemical Reactors
  15. Complex Flow Patterns
  16. Fluid-Fluid Reactions: Kinetics & Basics of Non Ideal Flow
  17. Compartment Models, Models for Non Ideal Reactors
  18. Microbial Fermentation

1. Chemical Reaction Engineering MCQ on Basic Concepts

The section contains Chemical Reaction Engineering multiple choice questions and answers on mole balances, reactions rates and classification.

  • Mole Balances
  • Reaction Rates – 1
  • Reaction Rates – 2
  • Classification of Reactions
  • 2. Chemical Reaction Engineering MCQ on Elements of Reaction Kinetics

    The section contains Chemical Reaction Engineering questions and answers on rate coefficient modelling and kinetic models size reduction.

  • Modelling the Rate Coefficient – 1
  • Modelling the Rate Coefficient – 2
  • Reducing the Size of Kinetic Models
  • 3. Chemical Reaction Engineering MCQ on Kinetics of Homogeneous Reactions

    The section contains Chemical Reaction Engineering MCQs on liquid and gas phase reactions, theories comparison and ideal reactor types.

  • Liquid and Gas Phase Reactions
  • Comparison of Theories – 1
  • Comparison of Theories – 2
  • Ideal Reactor Types
  • 4. Chemical Reaction Engineering MCQ on Homogenous Reactions in Ideal Reactors

    The section contains Chemical Reaction Engineering multiple choice questions and answers on reactor design basics.

  • Introduction to Reactor Design
  • 5. MCQ on Ideal Reactors for a Single Reaction, Conversion and Reactor Sizing

    The section contains Chemical Reaction Engineering questions and answers on batch reactor design equations, flow reactors design equations, ideal reactors problems, flow reactors, right reactor series, space time and velocity.

  • Batch Reactor Design Equations
  • Design Equations for Flow Reactors
  • Problems on Ideal Reactors
  • Applications of Design Equations for Continuous – Flow Reactors
  • Choosing of Right Reactor Series or Connections (Maximum Profitability)
  • Space Time and Space Velocity
  • 6. Chemical Reaction Engineering Multiple Choice Questions on Rate Laws and Stoichiometry

    The section contains Chemical Reaction Engineering MCQs on rate laws, stoichiometry definitions, reaction order, elementary rate law, reversible reactions rate laws, constant – volume batch reaction systems, stoichiometry of batch and flow systems, batch and flow systems concentrations equations.

  • Rate Laws and Stoichiometry Definitions
  • Reaction Order and Elementary Rate Law
  • Non – Elementary Rate Laws
  • Reversible Reactions Rate Laws
  • Reaction Rate Constant and Activation Energy
  • Stoichiometry of Batch Systems
  • Equations for Batch Concentrations
  • Constant – Volume Batch Reaction Systems
  • Batch Reactors with Variable Volume
  • 7. Chemical Reaction Engineering MCQ on Isothermal Reactor Design

    The section contains Chemical Reaction Engineering multiple choice questions and answers on cstrs design.

  • Design of CSTRS in Series
  • 8. Chemical Reaction Engineering MCQ on Collection and Analysis of Rate Data

    The section contains Chemical Reaction Engineering questions and answers on half lives methods.

  • Method of Half Lives
  • 9. Chemical Reaction Engineering MCQ on Potpourri of Multiple Reactions

    The section contains Chemical Reaction Engineering MCQs on autocatalytic reactions, selectivity and reactor yield.

  • Autocatalytic Reactions
  • Selectivity and Reactor Yield
  • 10. Chemical Reaction Engineering MCQ on Catalysis & Solid Catalysed Reactions

    The section contains Chemical Reaction Engineering multiple choice questions and answers on catalysts and pore diffusion resistance.

  • Catalysts
  • Pore Diffusion Resistance
  • 11. Chemical Reaction Engineering MCQ on Fluid-Particle Reactions: Kinetics

    The section contains Chemical Reaction Engineering questions and answers on fluid particle reactors design, rate determination and gas film diffusion controls.

  • Design of Fluid Particle Reactors
  • 12. Chemical Reaction Engineering MCQ on Packed Bed Catalytic Reactor

    The section contains Chemical Reaction Engineering MCQs on adsorption mechanisms and catalytic reactors.

  • Adsorption Mechanisms
  • 13. Chemical Reaction Engineering MCQ on Catalyst Deactivation

    The section contains Chemical Reaction Engineering multiple choice questions and answers on catalyst deactivation mechanisms.

  • Mechanisms of Catalyst Deactivation
  • 14. MCQ on Distribution of Residence Time for Chemical Reactors

    The section contains Chemical Reaction Engineering questions and answers on heat effects.

  • Heat Effects
  • 15. Chemical Reaction Engineering MCQ on Complex Flow Patterns

    The section contains Chemical Reaction Engineering MCQs on equilibrium conversion.

  • Equilibrium Conversion
  • 16. Chemical Reaction Engineering MCQ on Fluid-Fluid Reactions: Kinetics & Basics of Non Ideal Flow

    The section contains Chemical Reaction Engineering multiple choice questions and answers on absorption systems with chemical reaction, fluid-fluid reactors design, reactors combination, non ideal flow reactors conversion, c, f and e curves properties.

  • Absorption Systems with Chemical Reaction
  • Design of Fluid Fluid Reactors
  • Properties of C, F and E Curves – 1
  • Properties of C, F and E Curves – 2
  • RTD for Combination of Reactors
  • 17. Chemical Reaction Engineering MCQ on Compartment Models, Models for Non Ideal Reactors

    The section contains Chemical Reaction Engineering questions and answers on series model in tanks and dispersion model.

  • Tanks in Series Model
  • Dispersion Model
  • 18. Chemical Reaction Engineering MCQ on Microbial Fermentation

    The section contains Chemical Reaction Engineering MCQs on microbial fermentation.

  • Microbial Fermentation – 1
  • Microbial Fermentation – 2
  • If you would like to learn "Chemical Reaction Engineering" thoroughly, you should attempt to work on the complete set of 1000+ MCQs - multiple choice questions and answers mentioned above. It will immensely help anyone trying to crack an exam or an interview.

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    1. “Elements of Chemical Reaction Engineering” by H S Fogler
    2. “Chemical Reaction Engineering” by O Levenspiel
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    5. “Chemical Reaction Engineering” by Doraiswamy Uner

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