chemical engineering chemical reaction MCQs – Page 19

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 Review each marked answer and report any item that may be outdated or unclear.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

361. Thermodynamic equilibrium constant in a system is affected by___________________?
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A. All A., B. & C.

B. Inerts

C. Temperature

D. Pressure

362. The reason why a catalyst increases the rate of reaction is that, it______________?
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A. Decreases the molecular collision diameter

B. None of these

C. Increases the activation energy

D. Decreases the energy barrier for reaction

363. The rate constant of a first order reaction depends on the ________________?
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A. Time

B. Temperature

C. Concentration of the product

D. Concentration of the reactant

364. An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation is ___________________?
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A. Maximum at the centre of the reactor

B. Maximum at the exit of the reactor

C. Constant throughout the reactor

D. Maximum at the inlet of the reactor

365. The rate constant of a chemical reaction decreases by decreasing the____________________?
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A. Duration of reaction

B. Temperature

C. Concentration of reactants

D. Pressure

366. From Arrhenius law, a plot of loge K versus 1/T gives a straight line with a slope of (-E/R). The unit of E/R is___________________?
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A. k cal

B. k cal. K

C. K

D. k cal/K

367. Which of the following is the most suitable for isothermal operation?
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A. Batch reactor

B. Plug-flow reactor

C. Fixed bed reactor

D. Back-mix reactor

368. The rate equation for the reaction represented by as shown in the bellow figure, is given by rx = K1 . Cx/(1 + K2 Cx). At high value of Cx (i.e.., K2Cx > > 1), the order of the reaction and the rate constant are respectively___________________?
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A. First order & K1/K2

B. Zero order & K1/K2

C. First order & K1

D. Zero order & K1

369. If the time required to change the concentration of reactant to half its original value is independent of the initial concentration, the order of reaction is _______________?
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A. Three

B. Zero

C. One

D. Two

370. When an exothermic reversible reaction is conducted adiabatically, the rate of reaction____________________?
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A. Continuously increases

B. Passes through a minimum

C. Continuously decreases

D. Passes through a maximum

371. For the chemical reaction X ? Y, it is observed that, on doubling the concentration of X, the reaction rate quadruples. If the reaction rate is proportional to Cx n, then what is the value of n? ?
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A. 16

B. 4

C. 4-Jan

D. 2

372. An isothermal aqueous phase reversible reaction, P ? R, is to be carried out in a mixed flow reactor. The reaction rate in k.mole/m3 .h is given by, r = 0.5CP 0.125CR. A stream containing only P enters the reactor. The residence time required (in hours) for 40% conversion of P is_________________?
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A. 0.8

B. 1.33

C. 2.67

D. 1.60

373. Conversion increases with increase in temperature in case of a/an ______________ reaction?
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A. Irreversible

B. Reversible exothermic

C. Autocatalytic

D. Reversible endothermic

374. Space time equals the mean residence time__________________?
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A. For CSTR

B. When the density of the reaction mixture is constant

C. For narrow diameter tubular reactor

D. For large diameter tubular reactor

375. The excess energy of the reactants required to dissociate into products is known as the ________________ energy?
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A. Activation

B. Thermal

C. Threshold

D. Binding

376. Pick out the wrong statement ?
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A. ticular duty</strong>

B. In an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in longitudinal direction

C. Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a

D. The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and

E. Space time in a flow reactor is a measure of its capacity and is equal to the residence time when the density of reaction mixture is constant

F. inity respectively

377. Carbon particles accumulated on the catalyst used in the gas oil cracking lies in the category of _____________________ poison?
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A. Selectivity

B. Chemisorbed

C. Stability

D. Deposited

378. In the reversible reaction of the type, A + B ? AB, in general__________________?
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A. Both forward and backward reactions will be exothermic

B. Neither of the reactions will be endothermic

C. The combination reaction will be exothermic, while the dissociation reaction will be

D. othermic</strong>

E. The combination reaction will be endothermic, while the dissociation reaction will be

F. thermic

379. A batch reactor is_______________?
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A. Suitable for gas-phase reactions on commercial scale

B. Most suitable for very large production rate

C. Suitable for liquid phase reactions involving small production rate

D. Least expensive to operate for a given rate

380. The performance of a cascade of CSTRs can be improved by adding__________________?
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A. More CSTRs in parallel

B. A P.F. reactor in series

C. A P.F. reactor in parallel

D. More CSTRs in series

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