A. Langmuir’s assumption applies to every adsorbed layer
B. There is no dynamic equilibrium between successive layer
C. The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer
(except the first one) is involved in each of the evaporation process
D. None of these
Related Mcqs:
- 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 - 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 - 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 - ‘If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process’. The diffusivity under this condition is called ‘Knudsen diffusivity’, which is affected by the_____________________?
A. Pressure
B. Temperature
C. Both A. & B.
D. Neither A. nor B. - 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. - A first order reaction A → B occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of A at the centre of the pellet is much less than at the external surface, the process is limited by__________________?
A. Diffusion within the pellet
B. Reaction
C. External mass transfer
D. None of the above - BET apparatus is used to determine the ___________________?
A. Specific surface of a porous catalyst
B. Pore size distribution
C. Pore diameter
D. Porosity of the catalyst bed - Helium-mercury method can be used to determine the _____________ of the catalyst particle?
A. Pore volume
B. Solid density
C. Porosity
D. All A., B., & C. - Which of the following factors control the deactivation of a porous catalyst pellet?
A. Decay reactions
B. Pore diffusion
C. Form of surface attack by poison
D. All A., B. and C. - Bulk diffusion in catalyst pore _______________ with increase in pressure?
A. Increases
B. Decreases
C. Remains unchanged
D. Increases exponentially
