chemical engineering chemical reaction Mcqs
451. Pick out the correct statement ?
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A. Law of mass action was suggested by Le-Chatelier

B. A catalyst changes the equilibrium point

C. rgy

D. The difference between the energy of reactants and that of the products is the activation

E. A catalyst does not change AH of the reaction
452. At a given temperature, K1, K2 and K3 are equilibrium constants for the following reactions 1, 2, 3 respectively. CH4(g) + H2O(g) ? CO(g) + 3H2(g), CO(g) + H2O(g) ? CO2(g) + H2(g) CH4(g) + 2H2O(g) ? CO2(g) + 4H2(g) Then K1, K2 and K3 are related as ?
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A. K3 = (K1.K2)0.5

B. K3(K1+K2)/2

C. K3 = K1.K2

D. K3 = (K1.K2)2

453. Which of the following will favour the reverse reaction in a chemical equilibrium reaction ?
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A. Increasing the concentration of one of the reactants

B. Removal of at least one of the products at regular interval

C. None of these

D. Increasing the concentration of one or more of the products
454. For the liquid phase zero order irreversible reaction A ? B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min-1. What will be the conversion for a PFR with a space velocity of 0.2 min-1? Assume that all the other operating conditions are the same for CSTR and PFR ?
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A. 0.3

B. 0.60

C. 0.15

D. 0.9

455. The reactions of high molecularity are rare, because________________?
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A. Many body collisions are not favoured energetically

B. Of requirement of very large concentration for such reactions

C. Of low probability of many body collisions

D. Of very large activation energy of many bodies

456. With increase in temperature, the equilibrium _______________ rises in case of endothermic reaction?
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A. Constant

B. Conversion

C. Both A. & B.

D. Neither A. nor B.

457. In an ideal tubular-flow reactor_________________?
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A. There is a uniform velocity across the radius

B. All A., B. and C.

C. Mixing takes place in radial direction

D. There is no mixing in longitudinal direction

458. A Catalyst ____________________?
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A. None of these

B. Shortens the time to reach the equilibrium

C. Changes the equilibrium constant of the reaction

D. Increases the equilibrium concentration of the product

459. For reactions in parallel viz A ? P (desired product) and A ? Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a_________________?
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A. Batch reactor is preferred over a single CSTR for high yield

B. Tubular reactor is preferred over a single CSTR for high yield

C. Both A. and B.

D. Single CSTR is the most suitable

460. Transition state theory relates the above quantities as___________________?
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A. k ? ?T

B. k ? T1.5

C. k ? e-E/RT

D. k ? T.eE/RT
461. The temperature dependence of reaction rate constant (K) by Arrhenius law is given by_______________?
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A. K ? eE/RT

B. K ? e-E/RT

C. K ? T . e-E/RT

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

462. Pick out the wrong statement pertaining to space velocity of flow reactors?
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A. None of these

B. The space velocity of 3 hr-1 means that three reactor volumes of feed at specified conditions

C. being fed into the reactor every hour

D. The space velocity of 3 hr-1 means that one third reactor volume of feed at specified

E. ditions are being fed into the reactor</strong>

F. The unit of space velocity is (time)-1

463. At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500K and 400K 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? ?
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A. 2.5

B. 2

C. 1.6

D. 2.24

464. If CA is the quantity of reactants initially present, the quantity left after n half periods will be equal to__________________?
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A. (CA/2)1/n

B. (CA)1/2n

C. ()n CA

D. (CA/2)n

465. Pick out the wrong statement?
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A. Exit age description function E. and internal age distribution function (I) are related as, E = -(dI/d?)

B. A higher temperature favours the reaction of higher activation energy

C. Chemisorption studies are useful in the determination of catalyst surface area and pore size distribution

D. A catalyst increases the potential energy barrier over which the reactants must pass to form products
466. A trickle bed reactor is the one, which_________________?
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A. Employs all the three phases (i.e. solid, liquid and gas)

B. Has altogether three streams either entering or leaving

C. Processes three reactants at different flow rates

D. Processes three reactants with same flow rate

467. An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will ______________ with decrease in space time?
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A. Increase

B. Increase exponentially

C. Decrease

D. Remain unchanged

468. The decomposition of A into B is represented by the exothermic reaction, A ? 2B. To achieve maximum decomposition, it is desirable to carry out the reaction ?
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A. At high P and high T

B. At low P and low T

C. At low P and high T

D. At high P and low T

469. The unit of frequency factor in Arrhenius equation is_______________?
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A. Same as that of activation energy

B. Dimensionless

C. Same as that of rate constant

D. None of these

470. Which of the following factors control the deactivation of a porous catalyst pellet?
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A. All A., B. and C.

B. Decay reactions

C. Pore diffusion

D. Form of surface attack by poison

471. A reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?
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A. None of these

B. Catalytic

C. Photochemical

D. Autocatalytic
472. Recycling back of outlet stream to the reactor from an ideal CSTR carrying out a first order liquid phase reaction will result in ______________ in conversion?
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A. No change

B. Increase

C. Either A. or B., depends on the type of reaction

D. Decrease