chemical engineering chemical reaction MCQs – Page 16

Practise multiple-choice questions from chemical engineering chemical reaction for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering chemical reaction Mcqs

301. Transition state theory gives the rate constant as__________________?
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A. K ? T . e-E/RT

B. K ? eE/RT

C. K ? e-E/RT

D. K ? ?T . e-E/RT

302. consecutive reaction, as shown in the bellow figure, is characterised by __________________?
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A. High exothermicity

B. Maxima in the concentration of A

C. Maxima in the concentration of C

D. Maxima in the concentration of B

303. Pick out the correct statement?
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A. Pore volume and porosity of a catalyst is measured by Brunauer-Emmett-Teller (BET)

B. The dispersion number for a reactor/vessel is uL/D

C. hnique

D. A lower temperature favours the reaction of lower activation energy

E. The rate controlling step in a reaction involving many steps is the fastest step

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

305. A catalyst loses its activity due to__________________?
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A. Loss in surface area of the active component

B. Covering of the catalytic active sites by a foreign substance

C. All A., B. and C.

D. Agglomeration of metal particles caused by thermal sintering of the solid surface

306. For a reaction of the type of bellow given figure, the rate of reaction (- rx) is given by___________________?
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A. (K1 + K2+K3) CX

B. K1CV K2CX

C. (K1 + K1) CX

D. (K1 K2) CX

307. A back mix reactor is___________________?
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A. Suitable for gas phase reactions

B. Same as ideal stirred tank reactor

C. Same as plug flow reactor (PFR)

D. Ideal at very low conversion

308. The units of frequency factor in Arrhenius equation_________________?
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A. Depend on temperature, pressure etc. of the reaction

B. Depend on the order of the reaction

C. Are the same as those of the rate constant

D. Are cycles per unit time

309. 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) ?
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A. k KAKB pApB / (1 + KApA + KBpB + KCpC)

B. k KAKB pApB / (1 + KApA + KBpB)

C. k KA pApB / (1 + KApA + KBpB)

D. k KAKB pApB / (1 + KApA + KBpB + KCpC)2

310. BET apparatus_______________________?
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A. Is made entirely of stainless steel

B. None of these

C. Measures the catalyst surface area directly

D. Operates at very high pressure

311. Considering the endothermic dissociation of CaCO3 in a closed vessel (CaCO3 ? CaO + CO2), the pressure of CO2 increases, if____________________?
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A. The temperature is increased

B. None of these

C. A catalyst is added

D. An inert gas is pumped keeping the temperature constant

312. In a reversible reaction, a catalyst increases the rate of forward reaction__________________?
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A. To a greater extent than that of the backward reaction

B. Only

C. And decreases that of the backward reaction

D. And the backward reaction equally

313. Specific rate constant for a second order reaction__________________?
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A. Is independent of temperature

B. Varies with temperature

C. Depends on the nature of the reactants

D. Both B. and C.

314. In flow reactors, the performance equations interrelate the rate of reaction to the___________________?
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A. All A., B. and C.

B. Extent of reaction

C. Reactor volume

D. Feed rate

315. Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments where the ratio of concentration of B to that of A in the initial feed was less than 0.5, the concentration of B increased first, reached a maximum and then declined with time. However, for all experiments where this concentration ratio was 0.5 or above, concentration of B decreased monotonically with time right from the beginning. What is the ratio of the two rate constants (k1/k2) ?
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A. 2-Jan

B. 2

C. 4

D. 1/4

316. Chemical reaction rate of a component depends upon the______________________?
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A. All A., B. and C.

B. Temperature of the system

C. Composition of the component only

D. Pressure of the system

317. With increase in initial concentration, the fractional conversion of a first order reaction in a given time___________________?
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A. Increases

B. Remain constant

C. Decreases

D. Unpredictable

318. Exothermic reactions are best carried out in ________________?
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A. A CSTR

B. A plug flow reactor followed by CSTR

C. CSTR followed by a plug flow reactor

D. CSTR in series

319. In a/an ______________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation?
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A. None of these

B. Adiabatic

C. Isothermal

D. Non-adiabatic

320. 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___________________?
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A. (1 + x)

B. (1 x)2

C. (1 x)

D. (1 + x)2

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