A. Have very high selectivity
B. Increase the activity of a catalyst
C. Provide large surface area with a small amount of active material
D. Inhibit catalyst poisoning
Related Mcqs:
- 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 - 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. - 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 - 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. - Promoter is added to the catalyst to improve its____________________?
A. Porosity
B. Sensitivity
C. Surface area
D. None of these - 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 - If Thiele modulus is ________________, then the pore diffusion resistance in a catalyst may be considered as negligible?
A. 0
B. ∞
C. < 0.5
D. > 0.5 - 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 - A reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?
A. Catalytic
B. Autocatalytic
C. Photochemical
D. None of these - 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
