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 173 of 350
- A. ∞
- B. 0
- C. > 1
- D. 1
Explanation: For a zero-order reaction, the rate is constant and independent of concentration.
Correct answer: 13442. The catalytic activity of enzymes is due to their capacity to lower the ______________ energy?
- 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- A. More than
- B. Less than
- C. Either B. or C.
- D. Equal to
Explanation: Chemical equilibrium is dynamic: forward and reverse reactions continue, but their rates are equal, giving no net change in composition.
Correct answer: Equal to- A. Has unit of time-1
- B. Is not a function of the unit of time
- C. Changes on changing the concentration units
- D. None of these
Explanation: For a first-order law, rate = kC, so k must have units of inverse time, such as s⁻¹.
Correct answer: Has unit of time-1- A. Twice
- B. Half
- C. Equal
- D. None of these
Explanation: When diffusion controls the observed rate, the measured activation energy is reduced because the rate is governed partly by transport…
Correct answer: Half- A. Removal of one of the products regularly
- B. Increase in the concentration of one of the reactants
- C. Increase in the concentration of one of the products
- D. None of these
Explanation: Adding a product shifts equilibrium toward the reactants to oppose the concentration increase, so the reverse reaction is favoured.
Correct answer: Increase in the concentration of one of the products3453. With increase in temperature, the equilibrium _______________ rises in case of endothermic reaction?
- A. Constant
- B. Neither A. nor B.
- C. Both A. & B.
- D. Conversion
Explanation: Heating an endothermic system favours the forward reaction, increasing both the equilibrium constant and, under usual conditions, the…
Correct answer: Conversion- A. Microbial fermentation reaction
- B. Photochemical reactions
- C. Enzyme fermentation reaction
- D. Ammonia synthesis reaction
Explanation: Microbial fermentation is commonly treated as autocatalytic because the microorganisms or biomass formed during the reaction promote…
Correct answer: Microbial fermentation reaction- A. Increase
- B. Increase exponentially
- C. Decrease
- D. Remain unchanged
Explanation: For an irreversible reaction in a tubular flow reactor, conversion increases with residence or space time because reactant has more time…
Correct answer: Decrease- A. Only chemical
- B. Only physical
- C. Neither A. nor B.
- D. Both A. & B.
Explanation: A heterogeneous catalytic reactor requires physical steps such as diffusion and adsorption, as well as chemical surface reaction and…
Correct answer: Both A. & B.3457. Holding time for flow reactors is _______________ the space time, for constant fluid density ?
- A. Equal to
- B. Triple
- C. Double
- D. None of these
Explanation: Space time is reactor volume divided by inlet volumetric flow, while holding time uses the actual fluid volume flow inside the reactor.
Correct answer: Equal to- 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
Explanation: A high-molecularity reaction requires several particles to collide simultaneously with suitable energy and orientation.
Correct answer: Of low probability of many body collisions- A. Equilibrium constant
- B. Activation energy
- C. Final products
- D. Heat of reaction
Explanation: A catalyst provides an alternative reaction pathway with lower activation energy, increasing the reaction rate in both directions.
Correct answer: Activation energy- A. Lack of intraparticle diffusion resistance
- B. Presence of two mobile phases
- C. Both A. and B.
- D. Neither A. nor B.
Explanation: In a slurry reactor, finely divided catalyst particles are suspended in a liquid, usually with a gas phase also present, giving two mobile…
Correct answer: Both A. and B.