Chemical Engineering - MCQ Practice Questions

In a batch reactor operating at constant temperature, the reaction A → B follows second-order kinetics with rate constant k = 0.05 L/(mol·min). If initial concentration of A is 2 M, what is the time required to reduce the concentration to 0.5 M?

Which of the following statements about residence time distribution (RTD) in reactors is incorrect?

For a first-order consecutive reaction A → B → C where k₁ = 0.1 min⁻¹ and k₂ = 0.05 min⁻¹, the maximum concentration of intermediate B occurs at approximately:

What is the primary advantage of using a plug flow reactor (PFR) over a continuous stirred tank reactor (CSTR) for reactions with activation energy greater than 50 kJ/mol?

In the Langmuir-Hinshelwood mechanism for catalytic reactions, what does the parameter K represent in the rate equation r = kK[A]/[1 + K[A]]?

For a reversible reaction A ⇌ B with forward rate constant k_f = 0.3 s⁻¹ and reverse rate constant k_r = 0.1 s⁻¹, what is the equilibrium constant K_c?

In industrial practice, which method is most effective for controlling selectivity toward desired product in competitive parallel reactions?

The autocatalytic reaction A + B → 2B (where B is catalyst) exhibits which characteristic behavior?

For a non-elementary bimolecular reaction where experimental data shows apparent order n = 1.5 with respect to concentration [A], which mechanism is most probable?

In a fed-batch reactor for ester synthesis, maintaining the molar ratio of reactants at a specific value improves conversion. This strategy is known as:

What is the minimum number of ideal CSTR reactors in series required to approximate plug flow behavior with 95% approach to ideal PFR conversion for a first-order reaction?

In the design of a photocatalytic reactor for degradation of pollutants, which parameter has the most significant effect on reaction rate?

For a gas-phase reaction in a fluidized bed reactor, the overall reaction rate is limited by mass transfer from bulk to catalyst surface. Which step shows zero-order kinetics behavior?

In a jacketed CSTR for an endothermic reaction, increasing the heat transfer area per unit volume of reactor primarily affects which parameter?

Which of the following best describes the role of the Damköhler number (Da) in reactor design?

For the decomposition of N₂O₅ following first-order kinetics with k = 0.0074 s⁻¹, what fraction of reactant remains after 300 seconds?

In cascade impaction for studying particle-phase reaction kinetics in reactors, which aerodynamic diameter range represents particles most suitable for chemical reaction on catalyst surfaces?

For an isothermal CSTR processing a second-order reaction with inlet concentration C_A0 = 1 M and space time τ = 10 seconds, if k = 0.1 L/(mol·s), the outlet concentration is approximately:

In fermentation processes, the Monod equation describes microbial growth rate kinetics. Which substrate concentration results in 90% of maximum growth rate?

Which reactor configuration minimizes backmixing while maintaining high mass transfer rates for liquid-liquid reactions between immiscible phases?