chemical engineering chemical reaction Mcqs
351. The synthesis of proteins and metabolism in biological objects occur in the presence of biocatalyst called_________________?
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A. A ferment or an enzyme

B. Fungi

C. None of these

D. Haemoglobin

352. The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are_______________?
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A. 1 & 1

B. 11 & 2

C. 2 & 1

D. 2 & 2

353. In a consecutive reaction system of the given figure bellow, when E1 is much greater than E2, the yield of B increases with the____________________?
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A. Decrease in initial concentration of A

B. Increase of temperature

C. Decrease of temperature

D. Increase in initial concentration of A

354. For high conversion in a highly exothermic solid catalysed reaction, use a ______________ bed reactor?
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A. Fixed bed reactor followed by a fluidised

B. Fluidised bed reactor followed by a fixed

C. Fixed

D. Fluidised

355. Pick out the wrong statement ?
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A. A catalyst does not alter the final position of equilibrium in a reversible reaction

B. A catalyst is specific in reaction

C. A catalyst initiates a reaction

D. A catalyst remains unchanged in chemical composition at the end the reaction

356. If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process. The diffusivity under this condition is called Knudsen diffusivity, which is affected by the_____________________?
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A. Pressure

B. Temperature

C. Both A. & B.

D. Neither A. nor B.

357. Pick out the wrong statement ?
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A. A.e-Ea/RT

B. n the rate of disappearance of CH3CHO is equal to K.CCH3I.CHI and acts as a catalyst</strong>

C. ctor should be placed in series before the larger reactor

D. Two mixed reactors of unequal size are available for producing a specified product, formed by

E. The mechanism for the decomposition of CH3CHO into CH4 and CO in presence of I2 is:

F. Arrhenius equation describing the effect of temperature on rate constant is given by,

358. The increase in the rate of reaction with temperature is due to__________________?
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A. Decrease in activation energy

B. Increase in the number of effective collisions

C. None of these

D. Increase in the average kinetic energy of the reacting molecules

359. Enzymes are destroyed, when the_______________?
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A. Reactants concentration is very high

B. Reaction rate is independent of the reactants concentration

C. Reactants concentration is very low

D. Temperature is very high
360. A space time of 3 hours for a flow reactor means that___________________?
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A. It takes three hours to dump the entire volume of the reactor with feed

B. Three reactor volumes of feed can be processed every hour

C. The time required to process one reactor volume of feed (measured at specified conditions) is

D. ours</strong>

E. Conversion is cent per cent after three hours

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
381. If n = overall order of a chemical reaction. a = initial concentration of reactant. t = time required to complete a definite fraction of the reaction. Then pick out the correct relationship ?
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A. t ? 1/an + 1

B. t ? 1/an 1

C. t ? an

D. t ? 1/an

382. The dimensions of rate constant for reaction 3A ? B are (l/gm mole)/min. Therefore the reaction order is______________________?
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A. 3

B. 2

C. 1

D. 0

383. An imbalanced chemical reaction equation is against the law of________________?
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A. Multiple proportion

B. Constant proportion

C. None of these

D. Conservation of mass
384. In a/an _____________ vessel, the fluid enters and leaves following plug flow?
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A. Open

B. Open-closed

C. Closed

D. Close-opened

385. For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be ______________ times?
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A. 16

B. 8-Jan

C. 16-Jan

D. 8

386. A first order reaction requires two unequal sized CSTR. Which of the following gives higher yield ?
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A. Either of the arrangement A. or B. will give the same yield

B. Data insufficient, cant be predicted

C. Large reactor followed by smaller one

D. Smaller reactor followed by larger one

387. Pick out the wrong statement ?
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A. a particular duty

B. ocatalytic reaction

C. ctor provides higher overall selectivity</strong>

D. For an ideal mixed reactor at steady state, the exit stream has the same composition as fluid

E. For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank

F. Plug flow reactor (PFR) is always smaller than mixed reactor for all positive reaction orders

388. The fractional volume change of the system for the isothermal gas phase reaction, A ? 3B, between no conversion and complete conversion is___________________?
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A. 0.5

B. 3

C. 2

D. 1

389. The single parameter model proposed for describing non-ideal flow is the ____________ model?
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A. Tank in series

B. Dispersion

C. Both A. & B.

D. Neither A. nor B.

390. In case of _____________ reactions, the reaction rate does not decrease appreciably as the reaction proceeds?
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A. Catalytic

B. Parallel

C. Auto catalytic

D. Series

391. Pick out the wrong statement ?
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A. Autocatalytic reactions are exemplified by microbial fermentation reactions

B. The slowest step has the greatest influence on the overall reaction rate in case of an

C. eversible series reaction

D. The fractional conversion at any time is same for both the constant as well as the variable

E. ume system in case of an irreversible unimolecular type first order reaction

F. Hydrolysis of ester in presence of alkali or acid is a zero order reaction
392. Pick out the wrong statement?
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A. Most of the enzyme catalysed reactions involve at least two substrates

B. Equilibrium concentrations in enzyme catalysed reactions can be calculated by using the

C. rmodynamic properties of substrates & products

D. mical agents, is maximum at a temperature of about 45C

E. Enzymes help in increasing the activation energy of the reaction

F. Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value &

393. When the reaction is dominated by intraparticle diffusion, the apparent order of reaction (nD) as measured is related to the true order (n) as ________________?
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A. nD = (n + 1)/2

B. nD = n + 1

C. nD = n/2

D. None of these

394. With decrease in temperature, the equilibrium conversion of a reversible endothermic reaction_________________?
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A. Decreases

B. Increases

C. Remain unaffected

D. Increases linearly with temperature

395. Which of the following is an independent variable for a batch tank reactor with uniform concentration and temperature ?
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A. None of these

B. Diameter of the reactor

C. Useful volume of the tank

D. Time
396. The response curve for a step input signal from a reactor is called C-curve. The variance of C-curve in a tanks in series model comprising of m tanks is equal to ___________________?
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A. m2

B. ?m

C. 1/m

D. m

397. Velocity of a reaction depends upon the_________________?
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A. Temperature at which the reaction is carried

B. All A., B. and C.

C. Concentration of the reactants

D. Nature of the reactants

398. . In the converter of the contact process for the manufacture of H2SO4 the equilibrium conversion of SO2__________ (i) __________ with increase in temperature and __________ (ii) __________ with increase in the mole ratio of SO2 to air?
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A. (i) decreases (ii) increases

B. (i) increases (ii) increases

C. (i) increases (ii) decreases

D. (i) decreases (ii) decreases

399. In case of a/an ______________ chemical reaction, conversion increases with the rise in temperature?
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A. Irreversible exothermic

B. Irreversible endothermic

C. Reversible exothermic

D. Reversible endothermic
400. In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for________________?
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A. Fast reactions in catalyst of small pore diameter

B. Slow reactions in catalyst of large pore diameter

C. Slow reactions in catalyst of small pore diameter

D. Fast reaction in catalyst of large pore diameter