Q 1: For a non-catalytic homogeneous reaction A ⟶ B, the rate expression at 300 K is -r_A\left(mol\;m^{-3}\;s^{-1}\right)=\frac{10C_A}{1+5C_A} , where CA is the concentration of A (in mol/m3). Theoretically, the upper limit for the magnitude of the reactor rate (-rA in mol m-3 s-1, rounded off to the first decimal place) at 300 K is _________.
Q 2: The variations of the concentrations (CA, CR, and CS) for three species (A, R, and S) with time, in an isothermal homogeneous batch reactor are shown in the figure below.
Select the reaction scheme that correctly represents the above plot. The numbers in the reaction schemes shown below represent the first-order rate constants in units of s‒1.
Q 3: Hydrogen iodide decomposes through the reaction 2HI ⇋ H2 + I2. The value of the universal gas constant R is 8.314 J mol‒1K‒1. The activation energy for the forward reaction is 184000 J mol‒1. The ratio (rounded off to the first decimal place) of the forward reaction rate at 600 K to that at 550 K is __________.
Q 4: The liquid phase reversible reaction A ⇋ B is carried out in an isothermal CSTR operating under steady-state conditions. The inlet stream does not contain B and the concentration of A in the inlet stream is 10 mol/lit. The concentrations of A at the reactor exit, for residence times of 1 s and 5 s are 8 mol/lit and 5 mol/lit, respectively. Assume the forward and backward reactions are elementary following the first-order rate law. Also, assume that the system has constant molar density. The rate constant of the forward reaction (in s‒1, rounded off to the third decimal place) is __________.
Q 5: A liquid phase irreversible reaction A → B is carried out in an adiabatic CSTR operating under steady-state conditions. The reaction is elementary and follows the first-order rate law. For this reaction, the figure below shows the conversion (XA) of A as a function of temperature (T) for different values of the rate of reaction (-rA in mol m-3 s-1) denoted by the numbers to the left of each curve. This figure can be used to determine the rate of the reaction at a particular temperature, for a given conversion of A.
The inlet stream does not contain B and the concentration of A in the inlet stream is 5 mol/m3. The molar feed rate of A is 100 mol/s. A steady state energy balance for this CSTR results in the following relation: T = 350 + 25XA where T is the temperature (in K) of the exit stream and XA is the conversion of A in the CSTR. For an exit conversion of 80 % of A, the volume (in m3, rounded off to the first decimal place) of CSTR required is ___________.
Q 6: A porous pellet with Pt dispersed in it is used to carry out a catalytic reaction. The following two scenarios are possible.
Scenario 1: Pt present throughout the pores of the pellet is used for catalyzing the reaction.
Scenario 2: Pt present only in the immediate vicinity of the external surface of the pellet is used for catalyzing the reaction.
At a large value of Thiele modulus, which one of the following statements is TRUE?
Q 7: A CSTR has a long inlet pipe. A tracer is injected at the entrance of the pipe. The E-curve obtained at the exit of the CSTR is shown in the figure below.
Assuming plug flow in the inlet pipe, the ratio (rounded off to the second decimal place) of the volume of the pipe to that of the CSTR is ________.