Chemical Reaction Engineering GATE-2012

Q 1: For an exothermic reversible reaction, which one of the following correctly describes the dependence of the equilibrium constant (K) with temperature (T) and pressure (P)?

A) K is independent of T and P
B) K increases with an increase in T and P
C) K increases with T and decreases with P
D) K decreases with an increase in T and is independent of P

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Q 2: The half-life of an n^th order reaction in a batch reactor depends on

A) only the rate constant
B) only the rate constant and the order of the reaction
C) only the rate constant and the initial reactant concentration
D) the rate constant, initial reactant concentration, and the order of the reaction

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Q 3: Consider the reaction scheme shown below

A\xrightarrow{k_1}B\xrightarrow{k_2}C

Both the reactions are first-order. The activation energies for k₁ and k₂ are 80 and 20 kJ/mol, respectively. To maximize the yield of B, it is preferable to use

A) CSTR and high temperature
B) PFR and high temperature
C) CSTR and low temperature
D) PFR and low temperature

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Q 4: The rate-controlling step for the solid-catalyzed irreversible reaction

A+B\rightarrow C

is known to be the reaction of adsorbed A with adsorbed B to give adsorbed C. If P_i is the partial pressure of component i and K_i is the adsorption equilibrium constant of component i, then the form of the Langmuir-Hinshelwood rate expression will be

A) Rate\propto\frac{P_AP_B}{1+K_AP_A+K_BP_B+K_CP_C}
B) Rate\propto\frac{P_AP_B}{\left(1+K_AP_A+K_BP_B+K_CP_C\right)^2}
C) Rate\propto\frac{P_AP_B}{\left(1+K_AP_A+K_BP_B+K_CP_C\right)^{0.5}}
D) Rate\propto\frac{P_AP_B}{P_C}

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Q 5: The elementary reversible exothermic gas-phase reaction

A+3B\leftrightarrow2C

is to be conducted in a non-isothermal, non-adiabatic plug flow reactor. The maximum allowable reactor temperature is T_max. To minimize the total reactor volume, the variation of reactor temperature (T) with axial distance from the inlet (z) should be

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Statement linked questions Q 6 & 7:

The first order liquid phase reaction A → P is conducted isothermally in a plug flow reactor of 5 litre volume. The inlet volumetric flow rate is 1 litre/min and the inlet concentration of A is 2 mole/litre.

Q 6: If the exit concentration of A is 0.5 mole/litre, then the rate constant, in min⁻¹, is

A) 0.06
B) 0.28
C) 0.42
D) 0.64

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Q 7: The plug flow reactor is replaced by 3 mixed flow reactors in series, each of 2.0 litres volume. The exact conversion of A (in %) is

A) 35.9
B) 52.6
C) 73.7
D) 94.8

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