chemical engineering chemical reaction MCQs – Page 14

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 Review each marked answer and report any item that may be outdated or unclear.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
261. Pick out the wrong statement ?
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A. In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time

B. In a semi-batch reactor, one reactant is charged batch wise, while the other reactant is fed continuously

C. In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system

D. In a continuous flow reactor, both the reactants and the products flow out continuously

262. When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is__________________?
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A. 1

B. 0

C. > 1

D. < 1

263. The rate of forward reaction, at chemical equilibrium is ______________ the rate of backward reaction?
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A. More than

B. Equal to

C. Less than

D. Either B. or C.

264. A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type, A ? R, is taking place. The reactor is to be provided with a jacket in which coolant is flowing. Following data is given: CA0= 5 kmole/m3; XA = 0.5; Feed temperature = reactor temperature = 40C. Rate constant at 40C = 1 min-1; (?H) = 40kJ/mole; ? = 1000kg/m3 CP = 4 J/gm.C ; q = 10-3 m3/min (? and CP are same for the reactant and product streams). The amount of heat to be removed is_________________?
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A. 5/3 kW

B. 2/3 kW

C. 1 kW

D. 4 kW

265. When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only _______________ the true value?
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A. Half

B. Equal

C. Twice

D. None of these

266. The effect of increasing pressure on the gaseous equilibrium of the reaction 2X + 3Y ? 3X + 2Y indicates that____________________?
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A. None of these

B. Forward reaction is favoured

C. Pressure has no effect

D. Backward reaction is favoured

267. In an ideal mixed reactor (at steady state), the ___________________?
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A. All A., B. and C.

B. Space time is equivalent to holding time for constant density systems

C. Composition throughout the reactor remains same

D. Exit stream has the same composition as the fluid within the reactor

268. Rate of a chemical reaction is not influenced by the__________________?
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A. Temperature

B. Number of molecules of reactants taking part in a reaction

C. Catalyst

D. Reactants concentration

269. For the chemical reaction P ? Q, it is found that the rate of reaction doubles as the concentration of P is doubled. If the reaction rate is proportional to Cp n, then what is the value of n for this chemical reaction ?
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A. 3

B. 0

C. 1

D. 2

270. What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on ?
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A. Litre/mole

B. Litre/mole.second

C. Litre/second

D. Moles/litre.second

271. Which of the following factors control the design of a fluid-solid reactor ?
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A. Size distribution of solids being treated

B. Reaction kinetics for single particle

C. All A., B. and C.

D. Flow patterns of solids and fluid in the reactor

272. The importance of diffusion in a catalyst are increased by ____________________?
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A. Small pore diameter

B. All A., B. and C.

C. Large catalyst particle size

D. An active surface of the catalyst

273. Pick out the correct statement ?
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A. A chemical reaction accompanied by evolution of heat is called an endothermic reaction

B. The rate constant for a first order reaction does not change on changing the concentration units

C. A chemical reaction accompanied by absorption of heat is called an exothermic reaction

D. Chemical equilibrium state is dynamic in nature

274. Signal normally used to study non-ideal flow by stimulus response technique is _______________ input?
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A. Pulse

B. Step

C. Both A. & B.

D. Neither A. nor B.

275. A backmix reactor_________________?
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A. Is most suitable for gas phase reaction

B. Employs mixing in axial direction only

C. Is same as ideal stirred tank reactor

D. Is same as plug-flow reactor

276. Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene: 95 kmole / hr, water vapour: 97.5 k mole / hr and diethyl ether: 2.5 kmole/hr. The reactions occuring can be represented by: C2H5OH ? C2H4 + H2O 2C2H5OH ? C2H5 O C2H5 + H2O The percent conversion of ethanol in the reactor is________________?
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A. 97.5

B. 2.5

C. 95

D. 100
277. A batch adiabatic reactor at an initial temperature of 373K is being used for the reaction, A ? B. Assume the heat of reaction is 1kJ/mole at 373K and heat capacity of both A and B to be constant and equal to 50J/mole.K. The temperature rise after a conversion of 0.5 will be ____________?
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A. 20C

B. 10C

C. 5C

D. 100C

278. N plug flow reactors in series with a total volume V gives the same conversion as a single plug flow reactor of volume V for _______________ order reactions?
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A. Third

B. Second

C. First

D. Any
279. In case of a _____________ reactor, the composition in the reactor and at the exit of the reactor is the same ?
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A. Tubular

B. Back-mix

C. Batch

D. Semi-batch

280. For multiple reactions, the flow pattern within the vessel affects the ____________________?
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A. Size requirement

B. Distribution of reaction products

C. Both A. and B.

D. Neither A. nor B.