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Chemical Engineering :: Chemical Reaction Engineering

  1. 'Unreacted core model' represents the reaction involving

  2. A.

     Combustion of coal particles

    B.

     Roasting of sulphide ores

    C.

     Manufacture of carbon disulphide from elements

    D.

     None of these


  3. If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to

  4. A.

     The intrinsic activation energy E

    B.

     (E + ED) where ED is activation due to diffusion

    C.

     (E + ED)/2

    D.

     ED/2


  5. Pick out the wrong statement.

  6. A.

     In a multistep reaction, the slowest step is the rate determining step

    B.

     In general, the rate of a reaction becomes triple for every 10°C rise in temperature

    C.

     Slow chemical reactions have generally high values of activation energy

    D.

     Molecularity of a reaction can not be zero but the order of a reaction can be zero


  7. Half life period of a chemical reaction is

  8. A.

     The time required to reduce the concentration of the reacting substance to half its initial value

    B.

     Half of the space time of a reaction

    C.

     Half of the residence time of a reaction

    D.

     None of these


  9. Fluid flow in a real packed bed can be approximated as __________ model.

  10. A.

     Plug flow

    B.

     Dispersion

    C.

     Mixed flow

    D.

     Tank in series


  11. Participation of __________ is involved in the occurrence of a chemical reaction.

  12. A.

     Protons

    B.

     Neutrons

    C.

     Electrons

    D.

     None of these


  13. With decrease in temperature, the equilibrium conversion of a reversible endother- mic reaction

  14. A.

     Decreases

    B.

     Increases

    C.

     Remains unaffected

    D.

     Increases linearly with temperature


  15. n' number of plug flow reactors (P.F.R) in series with a total volume 'V' gives the same conversion as one P.F.R. of volume

  16. A.

     V/n

    B.

     V

    C.

     V.n

    D.

     1/V


  17. For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the

  18. A.

     Catalyst size is reduced or the catalyst diffusivity is reduced

    B.

     Catalyst size is reduced or the catalyst diffusivity is increased

    C.

     Catalyst size is increased or the catalyst diffusivity is reduced

    D.

     Catalyst size is increased or the catalyst diffusivity is increased


  19. Pick out the wrong statement.

  20. A.

     Or a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity

    B.

     Or an ideal mixed reactor at steady state, the exit stream has the same composition as fluid within the reactor and the space time is equivalent to holding time for constant density system

    C.

     Lug flow reactor (PFR) is always smaller than mixed reactor for all positive reaction orders for a particular duty

    D.

     Eaction rate does not decrease appreciably as the reaction proceeds in case of an autocatalytic reaction