A pulse tracer is introduced in an ideal CSTR (with a mean residence time I) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be__________________?

Related Mcqs:

1. The exit age distribution curve E(t) for an ideal CSTR with the average residence time, η, is given by__________________?

   A. e-t/η
   B. e-t/η/η
   C. 1 – e-t/η
   D. 1 – (e-t/η/η)

2. Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments where the ratio of concentration of B to that of A in the initial feed was less than 0.5, the concentration of B increased first, reached a maximum and then declined with time. However, for all experiments where this concentration ratio was 0.5 or above, concentration of B decreased monotonically with time right from the beginning. What is the ratio of the two rate constants (k1/k2) ?

   A. 1/4
   B. 1/2
   C. 2
   D. 4

3. The conversion for a first order liquid phase reaction. A → B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be_____________________?

   A. 60
   B. 75
   C. 90
   D. 100

4. With the same reaction time, initial concentration and feed rate, the reaction 2A → B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be__________________?

   A. Higher in P.F. reactor
   B. Higher in CSTR
   C. Same in both the reactors
   D. Data insufficient; can’t be predicted

5. If the time required to change the concentration of reactant to half its original value is independent of the initial concentration, the order of reaction is _______________?

   A. Zero
   B. One
   C. Two
   D. Three

6. The residence time distribution of an ideal CSTR is _____________________?

   A. (1/η) exp (-t/η)
   B. η exp (-t/η)
   C. exp (-t/η)
   D. (1/η) (-t/η)

7. For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by __________________?

   A. A Dirac delta function
   B. A step function
   C. A ramp function
   D. None of the above

8. The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k) is (Data: Heat of reaction at 298 K = – 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100kJ/kmole. K (may be assumed to be independent of temperature)) ?

   A. 400
   B. 500
   C. 600
   D. 1000

9. For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min-1. What will be the conversion for a PFR with a space velocity of 0.2 min-1? Assume that all the other operating conditions are the same for CSTR and PFR ?

   A. 0.15
   B. 0.30
   C. 0.60
   D. 0.90

10. What is the order of a chemical reaction in which doubling the initial concentration of the reactants doubles the half life time of the reaction ?

    A. 0
    B. 1
    C. 2
    D. 3