# Chemical Reaction Engineering GATE-1991

**Q 1:** The reaction of A and B produces the desired product R as well as the unwanted product S. What level of reactant concentrations (high, medium, low) should we use for the following reaction scheme in order to maximize the conversion of A to R. Reaction Scheme:

**Q 2:** Qualitatively, find the optimum temperature progression to maximize C_{T} for the elementary reaction scheme given below:

E_{1} = 25; E_{2} = 10; E_{3} = 25; E_{4} = 35; E_{5} = 40; E_{6} = 25; (E = Activation energy)

**Q 3:** Your company has two mixed-flow reactors of unequal size for producing a specified product formed by a homogeneous second-order reaction. How should these reactors be connected to achieve a maximum production rate?

###### Fill in the Blanks Q 4:

**Q 4:** Far a zero-order solid catalyzed reaction having a Thiele Modulus equal to one, the value of effectiveness factor is _________.

**Q 5:** For a reversible exothermic elementary catalytic reaction of the type

find the optimum operating reaction temperature at a conversion level, X_{A} =0.5. Data:

Maximum allowable temperature = 300 K.

**Q 6:** The rate of a liquid phase reaction of type A + B → Products is found to be independent of the concentration of A and B, and equal to 1 K mol/(m3) (mm) at 300 K. Find the conversion in a mixed flow reactor having volume equal to 2 m3 with feed concentration of A and S equal to 5K mol/m3, feed flow rate equal to 1 m3/min., and reactor temperature equal to 300 K. If the activation energy of the reaction is given as 83.1 kJ/mol. Find the volume of an isothermal plug flow reactor for the same conversion and feed conditions as in the case of the above-mentioned reactor but with the reactor temperature kept at 320 K.

**Q 7:** An aqueous solution (density = 1000 kg/m^{3}, specific heat 4 kJ/kg°C) at 300 K is continuously fed at a flow rate of 1 m^{3}/min to a continuous flow stirred tank of volume 1 m^{3} containing a heater having a heating capacity of 1000 kW. If the liquid in the tank is also at 300 K to start with, find the equation that predicts the exit temperature of the solution as a function of time after the heater is switched on.