A catalyst in a chemical reaction____________________?

Related Mcqs:

1. When an exothermic reversible reaction is conducted adiabatically, the rate of reaction____________________?

   A. Continuously increases
   B. Continuously decreases
   C. Passes through a maximum
   D. Passes through a minimum

2. For a heterogeneous catalytic reaction____________________?

   A. Free energy of activation is lowered in the presence of catalyst, which remains unchanged at
   the end of reaction
   B. A relatively small amount of catalyst can cause the conversion of large amount of reactants
   which does not mean that catalyst concentration is important
   C. The catalyst does not form an intermediate complex with the reactant
   D. The surface of the catalyst does not play an important role during reaction

3. Effectiveness factor E. of a catalyst pellet is defined as, E = (actual rate within pore of the catalyst)/(rate if not snowed by pore diffusion), Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus) ___________________?

   A. tan hT/T
   B. tan T/T
   C. tan hT/tan T
   D. None of these

4. A catalyst is said to be a negative catalyst, if it ___________________?

   A. Retards the rate of reaction
   B. Reduces the value of equilibrium constant
   C. Does not initiate the reaction
   D. All A., B. and C.

5. 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
   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. Effectiveness factor for a zero order reaction cannot be 7/8 as it must always be 1

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

   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

7. Catalyst is a substance, which ________________ chemical reaction?

   A. Increases the speed of a
   B. Decreases the speed of a
   C. Can either increase or decrease the speed of a
   D. Alters the value of equilibrium constant in a reversible

8. The catalyst in a first order chemical reaction changes the_________________?

   A. Equilibrium constant
   B. Activation energy
   C. Heat of formation of the product
   D. Heat of reaction

9. Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the ___________________?

   A. Activation energy
   B. Equilibrium constant
   C. Heat of reaction
   D. None of these

10. For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the ______________ adsorption?

    A. Physical
    B. Chemical
    C. Both A. and B.
    D. Neither A. nor B.