Free Chemical Reaction Engineering MCQs with Answers
395 Chemical Reaction Engineering MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Last updated
395 questions · page 11 of 20
- A. High pressure batch reactor
- B. Atmospheric pressure tank reactor
- C. High pressure tubular reactor
- D. Atmospheric pressure CSTR
Explanation: An autoclave is a pressure vessel commonly used for batch processing under elevated pressure, often also at elevated temperature.
Correct answer: High pressure batch reactor- A. P.F. reactors in series
- B. CSTR in series
- C. CSTR followed by P.F. reactor
- D. P.F. reactor followed by CSTR
Explanation: An autocatalytic reaction is slow at the feed inlet because little product catalyst is present, so a CSTR first builds up product…
Correct answer: CSTR followed by P.F. reactor- A. Reaction kinetics for single particle
- B. Size distribution of solids being treated
- C. Flow patterns of solids and fluid in the reactor
- D. All A., B. and C.
Explanation: Fluid-solid reactor design must account for intrinsic particle kinetics, the distribution of solid sizes, and the contacting or flow…
Correct answer: All A., B. and C.- A. Activated complex theory
- B. Collision theory
- C. Thermodynamics
- D. None of these
Explanation: Activated complex theory explains catalysis by showing that a catalyst provides an alternative reaction pathway with a lower activation…
Correct answer: Activated complex theory- A. 0
- B. < 0.5
- C. ∞
- D. > 0.5
Explanation: A small Thiele modulus indicates that the reaction is not fast enough for a significant concentration gradient inside the pores; pore…
Correct answer: < 0.5- A. Catalyst
- B. Temperature
- C. Number of molecules of reactants taking part in a reaction
- D. Reactants concentration
Explanation: Reaction rate is directly affected by temperature, reactant concentration and catalysts, but the mere number of molecules shown in the…
Correct answer: Number of molecules of reactants taking part in a reaction- A. Equilibrium constant is 1
- B. Conversion of the reactant at equilibrium condition is zero
- C. All A., B. and C.
- D. Reactant concentration at equilibrium condition is zero
Explanation: An irreversible reaction can be treated as a reversible reaction whose equilibrium lies completely toward products, so the reactant…
Correct answer: Reactant concentration at equilibrium condition is zero- A. Both A. and B.
- B. Distribution of reaction products
- C. Size requirement
- D. Neither A. nor B.
Explanation: For multiple reactions, mixing and residence-time patterns determine how much each reaction proceeds, affecting both product distribution…
Correct answer: Both A. and B.- A. Does not initiate the reaction
- B. Reduces the value of equilibrium constant
- C. Retards the rate of reaction
- D. All A., B. and C.
Explanation: A negative catalyst, or inhibitor, lowers the reaction rate by increasing the effective resistance to reaction.
Correct answer: Retards the rate of reaction- A. Threshold
- B. Potential
- C. Binding
- D. Activation
Explanation: Activation energy is the minimum excess energy reactant molecules must acquire to reach the activated state and undergo reaction.
Correct answer: Activation- A. One
- B. Zero
- C. Two
- D. Three
Explanation: For a first-order reaction, the half-life is t₁/₂ = 0.693/k and contains no initial concentration term.
Correct answer: One- A. Suitable for gas phase reactions
- B. Same as ideal stirred tank reactor
- C. Same as plug flow reactor (PFR)
- D. Ideal at very low conversion
Explanation: A back-mix reactor continuously mixes incoming material with reactor contents, making its composition uniform throughout.
Correct answer: Same as ideal stirred tank reactor- A. Increase in initial concentration of A
- B. Decrease of temperature
- C. Increase of temperature
- D. Decrease in initial concentration of A
Explanation: When E1 is greater than E2, the first reaction rate increases more sharply with temperature than the subsequent reaction, improving the…
Correct answer: Increase of temperature- A. Pore volume
- B. Solid density
- C. Porosity
- D. All A., B., & C.
Explanation: Helium measures the volume of the solid framework because it penetrates accessible pores, while mercury determines the pore volume it…
Correct answer: All A., B., & C.- A. Batch reactor
- B. Fluidised bed reactor
- C. Stirred tank reactor
- D. Tubular flow reactor
Explanation: A tubular flow reactor is compact and has no moving agitator or large vessel internals, making it suitable for continuous gas-phase…
Correct answer: Tubular flow reactor- A. Half of the space time of a reaction
- B. The time required to reduce the concentration of the reacting substance to half its initial value
- C. Half of the residence time of a reaction
- D. None of these
Explanation: Half-life is defined as the time required for the concentration of a reactant to fall to one-half of its initial value.
Correct answer: The time required to reduce the concentration of the reacting substance to half its initial value217. In a continuous flow stirred tank reactor, the composition of the exit stream_________________?
- A. Depends upon the flow rate of inlet stream
- B. Is different than that in the reactor
- C. Is same as that in the reactor
- D. None of these
Explanation: For an ideal continuous stirred-tank reactor, perfect mixing makes the concentration uniform throughout the reactor.
Correct answer: Is same as that in the reactor- A. None of these
- B. Static steady
- C. Dynamic unsteady
- D. Dynamic steady
Explanation: At equilibrium, the forward and reverse reactions continue at equal rates, so the macroscopic composition remains constant while molecular…
Correct answer: Dynamic steady- A. 7
- B. 6
- C. 3
- D. 7/3
Explanation: For a first-order reaction in a mixed-flow reactor, V = Q(Cin − Cout)/(kCout).
Correct answer: 7- A. Whole surface of the catalyst does not have the same activity for adsorption and there is
- B. attraction between the adsorbed molecule
- C. Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect
- D. on the rate of adsorption per site
- E. All the adsorption does not take place by the same mechanism
- F. Extent of adsorption is more than one complete monomolecular layer on the surface
Explanation: Langmuir theory assumes a uniform surface with identical adsorption sites, no interaction between adsorbed molecules, and formation of…
Correct answer: Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect