What is the dispersion number for a CSTR ?

Related Mcqs:

1. 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

2. 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

3. 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)

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. 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

6. An irreversible first order reaction is being carried out in a CSTR and PFR of same volume. The liquid flow rates are same. The relative conversion will__________________?

   A. Be more in CSTR than in PFR
   B. Be more in PFR than in CSTR
   C. Be same in both cases
   D. Depend on the temperature

7. The sequence in which three CSTR’s of volumes 5, 10 and 15 m3 will be connected in series to obtain the maximum production in a second order irreversible reaction is ____________________?

   A. 15, 10, 5
   B. 5, 10, 15
   C. 10, 5, 15
   D. 10, 15, 5

8. 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__________________?

   A. 2η
   B. 0.5η
   C. η/0.693
   D. 0.693η

9. A first order homogeneous reaction of the type X → Y → Z (consecutive reaction) is carried out in a CSTR. Which of the following curves respectively show the variation of the concentration of X, Y and Z with time ?

   A. I, II, III
   B. III, II, I
   C. III, I, II
   D. II, III, I

10. A first order reaction requires two unequal sized CSTR. Which of the following gives higher yield ?

    A. Large reactor followed by smaller one
    B. Smaller reactor followed by larger one
    C. Either of the arrangement A. or B. will give the same yield
    D. Data insufficient, can’t be predicted