Promoter is added to the catalyst to improve its____________________?

Related Mcqs:

1. 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

2. 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.

3. 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

4. The rate at which a chemical substance reacts is proportional to its____________________?

   A. Active mass
   B. Equivalent weight
   C. Molecular weight
   D. None of these

5. A catalyst in a chemical reaction____________________?

   A. Decreases the activation energy
   B. Alters the reaction mechanism
   C. Increases the frequency of collisions of reacting species
   D. All A., B. and C.

6. For a first order chemical reaction in a porous catalyst, the Thiele modulus is 10. The effectiveness factor is approximately equal to ____________________?

   A. 0
   B. 1
   C. 0.1
   D. 0.5

7. Organic catalysts differ from the inorganic catalyst in the sense that the former is________________?

   A. Active at cryogenic temperatures only
   B. Prohibitively costly
   C. Proteinous in nature
   D. Active at very high temperature only

8. Carbon particles accumulated on the catalyst used in the gas oil cracking lies in the category of _____________________ poison?

   A. Deposited
   B. Chemisorbed
   C. Selectivity
   D. Stability

9. A catalyst in a chemical reaction _______________ free energy change in the reaction?

   A. Increases
   B. Decreases
   C. Either A. or B.; depends on the type of catalyst
   D. Neither A. nor B.

10. Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene: 95 kmole / hr, water vapour: 97.5 k mole / hr and diethyl ether: 2.5 kmole/hr. The reactions occuring can be represented by: C2H5OH → C2H4 + H2O 2C2H5OH → C2H5 – O – C2H5 + H2O The percent conversion of ethanol in the reactor is________________?

    A. 100
    B. 97.5
    C. 95
    D. 2.5