A. Absorption of A
B. Surface reaction between absorbed A and absorbed B
C. Surface reaction between absorbed A and B in the gas phase
D. Surface reaction between A in the gas phase and absorbed B
Related Mcqs:
- The rate controlling step for the heterogeneous irreversible catalytic reaction A(g) + B(g) → C(g) is the surface reaction of absorbed A with absorbed B to give adsorbed C. The rate expression for this reaction can then be written as (where, KA, KB and KC are the equilibrium constants and is the rate constant of the rate controlling step) ?
A. k KA pApB / (1 + KApA + KBpB)
B. k KAKB pApB / (1 + KApA + KBpB)
C. k KAKB pApB / (1 + KApA + KBpB + KCpC)
D. k KAKB pApB / (1 + KApA + KBpB + KCpC)2 - The rate expression for a heterogeneous catalytic reaction is given by, – rA = K.KA PA(1 + KA.PA + KR.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A) ?
A. E
B. E + ΔHA
C. E + ΔHA – ΔHR)
D. ΔHA + ΔHR - For a vapour phase catalytic reaction (A + B → P) which follows the Ridel mechanism and the reaction step is rate controlling, the rate of reaction is given by (reaction rate is irreversible, product also absorbs) ?
A. -rA = (k . PA . PB)/(1 + KAPA + KPPP)
B. -rA = (k . PA
2 – k1PP)/(1 + KAPA + KPPP)
C. -rA = (k . PA . PB)/(1 + KAPB + KBPB . KPPP)
D. -rA = (k . PA . PB)/(1 + KAPA) - For a heterogeneous catalytic reaction, A + B → C, with equimole feed of A and B, the initial rate – rA0 is invariant with total pressure. The rate controlling step is______________________?
A. Surface Kc/(1 + TS) reaction between absorbed A and B in the gas phase
B. Surface reaction between absorbed A and absorbed B
C. Surface reaction between A in the gas phase and absorbed B
D. Desorption of C - Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually ________________ the concentration of catalyst, if it does not entail a chain mechanism?
A. Proportional to
B. Independent of
C. Inversely proportional to
D. Proportional to the square of - If a solid-gas non-catalytic reaction occurs at very high temperature, the rate controlling step is the ________________ diffusion?
A. Film
B. Ash layer
C. Pore
D. None of these - Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature ?
A. Pore diffusion
B. Film diffusion
C. Ash layer diffusion
D. Chemical reaction - Rate constant for a first order reaction does not depend upon reaction time, extent of reaction and the initial concentration of reactants; but it is a function of reaction temperature. In a chemical reaction, the time required to reduce the concentration of reactant from 100 gm moles/litre to 50 gm moles/litre is same as that required to reduce it from 2 gm moles/litre to 1 gm mole/litre in the same volume. Then the order of this reaction is ?
A. 0
B. 1
C. 2
D. 3 - In a chemical reaction, represented by as shown in the bellow figure, it is observed that the (i) Rate of reaction increases by a factor of 4 on doubling the concentration of the reactant. (ii) Rate of reaction increases by a factor of 9 on trebling the concentration of the reactant. Then the rate of the reaction is proportional to(where, CA = concentration of the reactant)_____________________?
A. CA
B. CA2
C. CA3
D. CA4 - ____________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction ?
A. Gas film diffusion
B. Ash diffusion
C. Chemical reaction
D. None of these
