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.
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395 questions · page 7 of 20
- A. Pulse
- B. Both A. & B.
- C. Step
- D. Neither A. nor B.
Explanation: Both pulse and step changes are standard stimulus inputs in tracer-response studies.
Correct answer: Both A. & B.- A. Reaction can be accomplished with small reactor
- B. Conversion can be obtained with a high feed rate
- C. Both A. and B.
- D. None of these
Explanation: Space velocity is feed rate per unit reactor volume, so a high value indicates a high throughput for a given reactor size.
Correct answer: Both A. and B.- A. 1.6
- B. 2
- C. 2.24
- D. 2.5
Explanation: Arrhenius behavior gives k500/k400 = 2, while transition-state theory adds the temperature factor T500/T400 = 1.25.
Correct answer: 2.5- A. None of these
- B. Adsorption
- C. Desorption
- D. Surface chemical reaction
Explanation: Adsorption, surface reaction, and desorption are all chemical steps in the usual mechanism for a fluid-solid catalytic reaction.
Correct answer: None of these- A. Be halved
- B. Remain the same
- C. Also be doubled
- D. Become one fourth
Explanation: At a fixed temperature, the equilibrium constant depends only on temperature and the reaction stoichiometry, not on the starting…
Correct answer: Remain the same- 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
Explanation: A catalyst carrier or support disperses a relatively small amount of active material over a large porous surface.
Correct answer: Provide large surface area with a small amount of active material- A. Slowest
- B. Fastest
- C. Intermediate
- D. Data insufficient; can't be predicted
Explanation: In the simplified consecutive-step model, the slowest step limits the overall reaction rate and is called the rate-determining step.
Correct answer: Slowest- A. Gas film diffusion
- B. Chemical reaction
- C. Ash diffusion
- D. None of these
Explanation: For a highly temperature-sensitive fluid-solid reaction, the chemical reaction step has the greatest temperature dependence and therefore…
Correct answer: Chemical reaction- A. (1 + x)2
- B. (1 - x)
- C. (1 + x)
- D. (1 - x)2
Explanation: Taking one initial mole of N₂O₄, the undissociated amount is 1 − x and dissociation produces 2x moles of NO₂.
Correct answer: (1 + x)- A. And decreases that of backward reaction
- B. To a greater extent than that of the backward reaction
- C. Only
- D. And backward reaction equally
Explanation: A catalyst provides an alternative pathway and lowers the activation barriers for both forward and reverse reactions.
Correct answer: And backward reaction equally- A. Temperature
- B. Concentration of the reactant
- C. Concentration of the product
- D. Time
Explanation: For a given reaction, the rate constant is primarily a function of temperature through the Arrhenius equation.
Correct answer: Temperature- A. 0
- B. 1
- C. 2
- D. 3
Explanation: Equal times for reducing concentration by the same factor, from 100 to 50 and from 2 to 1, indicate a constant half-life.
Correct answer: 1- A. ∞
- B. 0
- C. > 1
- D. 1
Explanation: For a zero-order reaction, the rate is constant and independent of concentration.
Correct answer: 1- A. Activation
- B. Potential
- C. Kinetic
- D. None of these
Explanation: Enzymes accelerate reactions by providing a pathway with lower activation energy.
Correct answer: Activation- A. Auto catalytic
- B. Parallel
- C. Series
- D. Catalytic
Explanation: In an autocatalytic reaction, a product helps catalyse the reaction, so the rate can remain high or initially increase as the reaction…
Correct answer: Auto catalytic- A. Autocatalytic
- B. Reversible endothermic
- C. Irreversible
- D. Reversible exothermic
Explanation: For a reversible endothermic reaction, heat acts like a reactant, so increasing temperature shifts equilibrium toward products and raises…
Correct answer: Reversible endothermic- A. A catalyst is added
- B. An inert gas is pumped keeping the temperature constant
- C. The temperature is increased
- D. None of these
Explanation: Raising temperature favors the endothermic decomposition of CaCO3, increasing the equilibrium partial pressure of CO2.
Correct answer: The temperature is increased- A. Atomic weight
- B. Molecular weight
- C. Equivalent weight
- D. Active mass
Explanation: The active mass is the effective concentration or activity of a reacting species, and the reaction rate depends on these quantities.
Correct answer: Active mass- A. Back-mix reactor
- B. Batch reactor
- C. Plug-flow reactor
- D. Fixed bed reactor
Explanation: A back-mix reactor is well suited to isothermal operation because complete mixing gives a nearly uniform temperature and makes heat…
Correct answer: Back-mix reactor- A. Is always equal to
- B. Is always less than
- C. Is always greater than
- D. May be greater or less than
Explanation: In an adiabatic exothermic reactor, the heat released by reaction raises the sensible enthalpy of the reacting mixture, so the outlet…
Correct answer: Is always greater than