A. Free energy of activation is lowered in the presence of catalyst, which remains unchanged at
the end of reaction
B. A relatively small amount of catalyst can cause the conversion of large amount of reactants
which does not mean that catalyst concentration is important
C. The catalyst does not form an intermediate complex with the reactant
D. The surface of the catalyst does not play an important role during reaction
Related Mcqs:
- 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 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 - The rate of the heterogeneous catalytic reaction A(g) + B(g) → C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?
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 - 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 - 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 - 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. - When an exothermic reversible reaction is conducted adiabatically, the rate of reaction____________________?
A. Continuously increases
B. Continuously decreases
C. Passes through a maximum
D. Passes through a minimum - Which of the following is a controlling factor in very fast heterogeneous reaction ?
A. Heat and mass transfer effects
B. Pressure
C. Temperature
D. Composition of reactant - A non-catalytic chemical reaction of the type as shown in the bellow figure is called a _____________ reaction?
A. Parallel
B. Series
C. Series-parallel
D. None of these
