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.
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 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 - B.E.T. method can be used to determine the ___________________ of a porous catalyst?
A. Solid density
B. Pore volume
C. Surface area
D. All A., B. and C. - 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 - Following isothermal kinetic data are obtained in a basket type of mixed flow reactor for a porous catalyst. Determine the role of pore diffusion and external mass transfer processes ?
A. Strong pore diffusion control and mass transfer not controlling
B. Both pore diffusion and mass transfer not controlling
C. Both pore diffusion and mass transfer controlling
D. Mass transfer controlling - When a catalyst increases the rate of chemical reaction, the rate constant_____________________?
A. Decreases
B. Increases
C. Remain constant
D. Become infinite - 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 - Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as_________________?
A. DE = DM + DK
B. 1/DE = 1/DN + DK
C. DE = DM . DE
D. DE = DN/DE - 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
