All Free Chemical Engineering MCQs with Answers
Every Chemical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
6,983 questions · page 179 of 350
- A. Endothermic
- B. Exothermic
- C. Biochemical
- D. Photochemical
Explanation: Combustion is the oxidation of organic material by oxygen, and it releases heat because the products are at a lower energy level than the…
Correct answer: Exothermic- A. Collision theory and activated complex theory
- B. Chain reaction theory
- C. None of these
- D. Radiation hypothesis
Explanation: Collision theory, activated complex theory, chain reaction theory, and radiation hypothesis are all used to explain reaction behaviour or…
Correct answer: None of these- A. 100%
- B. 95%
- C. 75%
- D. 20%
Explanation: The carbon consumed is 16.5/44 + 2.8/28 = 0.475 mol, while the initial carbon is 6/12 = 0.5 mol.
Correct answer: 95%- A. More when they are connected in series
- B. Less 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
Explanation: For a first-order reaction, equal CSTRs in series give successive concentration reductions, producing a higher overall conversion than…
Correct answer: More when they are connected in series- A. Larger reactors have more space time compared to smaller ones
- B. Space time for parallel lines is different
- C. Space time for each parallel line is same
- D. None of these
Explanation: Parallel reactors perform optimally when each line has the same space time, provided the reactors have the same kinetics and operating…
Correct answer: Space time for each parallel line is same- A. 5/4
- B. 7/4
- C. 5/2
- D. 7/2
Explanation: If rate is proportional to A^mB^n, doubling A gives 2^m = 2.82, so m is approximately 1.5; trebling B gives 3^n = 9, so n = 2.
Correct answer: 7/2- A. Slower rate of reaction
- B. Higher rate of reaction
- C. Higher equilibrium conversion
- D. Both B. and C.
Explanation: A higher Gibbs free energy of activation means a smaller rate constant according to transition-state theory, so fewer molecules cross the…
Correct answer: Slower rate of reaction- A. When the data are scattered
- B. Both A. and B.
- C. For testing specific mechanisms with simple rate expressions
- D. None of these
Explanation: The integral method compares concentration-time data with integrated forms of proposed rate laws, making it useful for testing simple…
Correct answer: Both A. and B.- A. Unimolecular reaction with first order
- B. Bimolecular reaction with second order
- C. Bimolecular reaction with first order
- D. Unimolecular reaction with second order
Explanation: Inversion involves sucrose reacting with water, so its molecularity is bimolecular.
Correct answer: Bimolecular reaction with first order- A. 0.03 sec-1
- B. 0.03 min-1
- C. 0.03 hr-1
- D. 0.05 min-1
Explanation: For a first-order reaction, the half-life relation is k = 0.693/t₁/₂. Thus k = 0.693/23 = 0.030 min⁻¹, making option b correct.
Correct answer: 0.03 min-1- A. Autokinetic
- B. Non-elementary
- C. Parallel
- D. Elementary
Explanation: An elementary reaction occurs in a single molecular event, so its rate equation follows the stoichiometric equation directly.
Correct answer: Elementary- A. Feasibility
- B. Rate
- C. Both A. & B.
- D. Neither A. nor B.
Explanation: Chemical kinetics determines how fast a reaction proceeds through its rate law and rate constant.
Correct answer: Rate- A. Lose an electron
- B. Gain a proton
- C. Lose a proton
- D. None of these
Explanation: Acid catalysis involves proton donation, so the catalytic species must have a tendency to lose a proton.
Correct answer: Lose a proton- A. Always spontaneous
- B. Slow
- C. Non-spontaneous
- D. Fast
Explanation: The Arrhenius relation shows that a lower activation energy gives a larger rate constant at the same temperature, so the reaction is…
Correct answer: Fast- A. All A., B. and C.
- B. Pressure only
- C. Composition only
- D. Temperature only
Explanation: An autocatalytic reaction rate depends on composition because a product participates in catalysis, and it also varies with temperature…
Correct answer: All A., B. and C.- A. Batch
- B. Slurry
- C. Fluidised bed
- D. Fixed bed
Explanation: Vegetable-oil hydrogenation commonly uses finely divided nickel suspended with the liquid oil and hydrogen, forming a slurry reactor.
Correct answer: Slurry- A. Biochemical
- B. Photochemical
- C. Autocatalytic
- D. Catalytic
Explanation: When a product accelerates the reaction that forms it, the reaction is called autocatalytic.
Correct answer: Autocatalytic- A. For testing complicated mechanisms
- B. When the data are scattered
- C. When rate expressions are very simple
- D. None of these
Explanation: The differential method obtains reaction rates by differentiating concentration data, so it is useful for testing complicated rate…
Correct answer: For testing complicated mechanisms- A. Time
- B. Length
- C. Diameter
- D. None of these
Explanation: In a tubular or plug-flow reactor, concentration and temperature vary primarily along the reactor axis.
Correct answer: Length- A. Non-catalytic homogeneous
- B. Non-catalytic heterogeneous
- C. Catalytic homogenous
- D. Catalytic heterogeneous
Explanation: In the chamber process, sulphur dioxide is oxidised in the gas phase with nitrogen oxides acting as catalysts.
Correct answer: Catalytic homogenous