Home / Chemical Engineering / Chemical Reaction Engineering :: Section-11

Chemical Engineering :: Chemical Reaction Engineering

  1. A batch reactor suffers from following disadvantage.

  2. A.

     Poor product quality control

    B.

     High labour and handling cost

    C.

     High shutdown time requirement for emptying, cleaning and refilling

    D.

     All of the above


  3. The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the

  4. A.

     Increased temperature reduces the activation energy

    B.

     Fraction of molecules having threshold energy increases

    C.

     Collision frequency increases

    D.

     Value of threshold energy decreases


  5. In a zero order reaction, reactants concentration does not change with time and the

  6. A.

     Time for half change is half the time taken for completion of the reaction

    B.

     Time for half change is independent of the initial concentration

    C.

     Time for completion of the reaction is independent of the initial concentration

    D.

     Reaction rate is trebled when the initial concentration is trebled


  7. Pick out the wrong statement.

  8. A.

     Autocatalytic reactions are exemplified by microbial fermentation reactions

    B.

     The slowest step has the greatest influence on the overall reaction rate in case of an irreversible series reaction

    C.

     He fractional conversion at any time is same for both the constant as well as the variable volume system in case of an irreversible unimolecular type first order reaction

    D.

     Ydrolysis of ester in presence of alkali or acid is a zero order reaction


  9. "A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?A. Inner catalyst core of radius R/8 does not participate in reaction."

  10. A.

     Inner catalyst core of radius R/8 does not participate in reaction

    B.

     Inner catalyst core of radius R/2 does not participate in reaction

    C.

     Inner catalyst core of radius 7R/8 does not participate in reaction

    D.

     Ffectiveness factor for a zero order reaction can not be 7/8 as it must always be 1


  11. For series reaction, the relative yield

  12. A.

     Is always greater for plug-flow reactor than for the single CSTR of the same volume

    B.

     Statement in A is wrong

    C.

     Decreases with increasing conversion

    D.

     Both A and C hold good


  13. In a reversible reaction, a catalyst increases the rate of forward reaction

  14. A.

     Only

    B.

     To a greater extent than that of the backward reaction

    C.

     And decreases that of the backward reaction

    D.

     And the backward reaction equally


  15. Shift conversion reaction

  16. A.

     Converts N₂ and H₂ into NH₃

    B.

     Converts CO to CO₂ with steam

    C.

     Is non-catalytic

    D.

     Is highly exothermic


  17. The following gas phase reactions are carried out isothermally in a CSTR.
    A → 2R ; r₁ = K₁pA ;
    K₁ = 20mole/(sec.m³ bar)
    A → 3S ; r₂ = K₂ pA ;
    K₂ = 40mole/ (sec.m³ .bar)
    What is the maximum possible value of FR(mole/sec.) ?

  18. A.

     1/3

    B.

     1/2

    C.

     2/3

    D.

     2


  19. When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is

  20. A.

     > 1

    B.

     < 1

    C.

     1

    D.

     0