chemical engineering MCQs – Page 147

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
2921. A back mix reactor is___________________?
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A. Ideal at very low conversion

B. Same as plug flow reactor (PFR)

C. Suitable for gas phase reactions

D. Same as ideal stirred tank reactor
2922. For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the _______________ is the controlling resistance?
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A. Either A., B. or C.

B. Chemical reaction

C. Film diffusion

D. Diffusion through ash layer
2923. Knudsen diffusion is directly proportional to _____________________?
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A. ?T

B. T2

C. T

D. 1/?T

2924. For a first order chemical reaction in a porous catalyst, the Thiele modulus is 10. The effectiveness factor is approximately equal to ____________________?
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A. 0.1

B. 0

C. 0.5

D. 1

2925. 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.

2926. In a semi-batch reactor _____________________?
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A. Velocity of reaction can be controlled

B. Maximum conversion can be controlled

C. Both the reactants flow counter-currently

D. Residence time is constant

2927. Half life period of a first order irreversible reaction A ? B is ______________________?
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A. ln 0.5/k

B. k/2

C. ln 2/k

D. ln k/2

2928. For the reaction, A + B ? 2B + C,___________________?
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A. rA = -rB

B. rA = rB

C. rA = rB/2

D. rA = 2rB

2929. Helium-mercury method can be used to determine the _____________ of the catalyst particle?
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A. Porosity

B. All A., B., & C.

C. Pore volume

D. Solid density

2930. Decomposition rate of a liquid X which decomposes as per the reaction as shown in the bellow figure is given by________________?
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A. K1 . CX

B. (K2 + K3) CX

C. (K1 + K2 + K3) CX

D. (K1 + K2) CX
2931. The rate constant of a reaction depends on the __________________?
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A. Time of reaction

B. Initial concentration of reactants

C. Temperature of the system

D. Extent of reaction

2932. The equilibrium constant of a catalytic chemical reaction _______________ due to the presence of?
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A. Remain unaffected

B. Decreases

C. Unpredictable from the data

D. Increases

E. atalyst.

2933. As the chemical reaction proceeds, the rate of reaction ___________________?
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A. Increases

B. May increase or decrease depending on the type of reaction

C. Decreases

D. Remain same

2934. The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 K to 500 K. Assuming transition state theory is valid, the value of E/R is __________________?
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A. 8987K

B. 9210K

C. 8621K

D. 8764K

2935. For the reversible reaction A ? 2B, if the equilibrium constant K is 0.05 mole/litre; starting from initially 2 moles of A and zero moles of B, how many moles will be formed at equilibrium ?
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A. 0.637

B. 0.253

C. 0.338

D. 0.152

2936. A second order reaction of the form A + B ? C is called a pseudo-first order reaction, when____________________?
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A. CA0 = CB0

B. CA0 > CB0

C. CB0 > CA0

D. CB0 ? CB0
2937. The rate constant of a chemical reaction increases by increasing the______________________?
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A. Pressure

B. Temperature

C. Reactants concentration

D. None of these

2938. The rate of a gas phase reaction is given by K . CA . CB. If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be _______________ times?
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A. 4

B. 2

C. 16

D. 8

2939. Space time in flow reactor is____________________?
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A. Usually equal to the residence time

B. The reciprocal of the space velocity

C. A measure of its capacity

D. Both A. and B.
2940. ______________ catalytic reaction is involved in the thermal cracking of gas oil ?
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A. Non-Homogeneous

B. Non-Heterogeneous

C. Homogeneous

D. Heterogeneous