Chemical Reaction Archives | Page 8 of 44

At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenius law is used. What will be this ratio, if transition state theory is used with the same value of „E/R‟ ?

August 23, 2021February 23, 2019 by admin

At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenius law is used. What will be this ratio, if transition state theory is used with the same value of „E/R‟ ?

A. 1.6
B. 2
C. 2.24
D. 2.5

Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as_________________?

August 23, 2021February 23, 2019 by admin

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

Which of the following is not a chemical step in a fluid solid catalytic reaction ?

August 23, 2021February 23, 2019 by admin

Which of the following is not a chemical step in a fluid solid catalytic reaction ?

A. Surface chemical reaction
B. Adsorption
C. Desorption
D. None of these

In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will________________?

August 23, 2021February 23, 2019 by admin

In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will________________?

A. Remain the same
B. Be halved
C. Also be doubled
D. Become one fourth

Catalyst carriers___________________?

August 23, 2021February 23, 2019 by admin

Catalyst carriers___________________?

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

Rate determining step in a reaction consisting of a number of steps in series is the ______________ step?

August 23, 2021February 23, 2019 by admin

Rate determining step in a reaction consisting of a number of steps in series is the ______________ step?

A. Fastest
B. Slowest
C. Intermediate
D. Data insufficient; can’t be predicted

____________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction ?

August 23, 2021February 23, 2019 by admin

____________ 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

If in the gaseous phase reaction, N2O4 ⇌ 2NO2, x is the part of N2O4 which dissociates, then the number of molecules at equilibrium will be___________________?

August 23, 2021February 23, 2019 by admin

If in the gaseous phase reaction, N2O4 ⇌ 2NO2, x is the part of N2O4 which dissociates, then the number of molecules at equilibrium will be___________________?

A. (1 + x)
B. (1 – x)
C. (1 + x)2
D. (1 – x)2

The catalyst in a second order reversible reaction increases the rate of the forward reaction___________________?

August 23, 2021February 23, 2019 by admin

The catalyst in a second order reversible reaction increases the rate of the forward reaction___________________?

A. And decreases that of backward reaction
B. And backward reaction equally
C. Only
D. To a greater extent than that of the backward reaction

The rate constant of a first order reaction depends on the ________________?

August 23, 2021February 23, 2019 by admin

The rate constant of a first order reaction depends on the ________________?

A. Concentration of the reactant
B. Temperature
C. Concentration of the product
D. Time