chemical engineering Mcqs
2753. The rate at which a chemical substance reacts is proportional to its____________________?
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A. None of these

B. Equivalent weight

C. Active mass

D. Molecular weight

2756. In case of a P.F.R., there__________________________?
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A. May be lateral mixing of fluid

B. Should not be any mixing along the flow path

C. Both A. and B.

D. Neither A. nor B.

2760. The rate of a homogeneous reaction is a function of__________________?
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A. Temperature and composition only

B. All temperature, pressure and composition

C. Temperature and pressure only

D. Pressure and composition only

2762. A first order reaction requires two equal sized CSTR. The conversion is____________________?
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A. More when they are connected in series

B. Same whether they are connected in series or in parallel

C. Less when they are connected in series

D. More when they are connected in parallel

2764. A stirred tank reactor compared to tubular-flow reactor provides____________________?
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A. All A., B. and C.

B. Permits operation at the optimum temperature for a long reaction time

C. Higher overall selectivity for a first order consecutive reaction

D. More uniform operating conditions

2765. Rate of a chemical reaction is not influenced by the__________________?
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A. Reactants concentration

B. Catalyst

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

D. Temperature

2766. Threshold energy in a reaction is equal to the_________________?
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A. Normal energy of reactants

B. Activation energy

C. Neither A. nor B.

D. Sum of A. & B.
2767. The residence time distribution of an ideal CSTR is _____________________?
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A. exp (-t/?)

B. ? exp (-t/?)

C. (1/?) exp (-t/?)

D. (1/?) (-t/?)

2768. The rate of an autocatalytic reaction as shown in the bellow figure, is given by rA = k . CA . CB. In this case, the__________________?
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A. Plot of rA Vs CA is a straight line with slope k

B. Plot of rA Vs CA is a hyperbola

C. Rate of disappearance of reactant A is maximum, where CA = CB

D. Both B & C
2769. Autocatalytic reactions are best carried out in a_________________?
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A. CSTR in series

B. Plug flow reactor

C. CSTR

D. Recycle reactor
2770. For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant ?
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A. ction

B. Increases /decreases with pressure depending on the stoichiometric co-efficients of the

C. Increases with pressure

D. Is independent of pressure

E. Decreases with pressure

2772. Higher free energy of activation of a chemical reaction (at a given temperature) implies ____________________?
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A. Slower rate of reaction

B. Higher rate of reaction

C. Higher equilibrium conversion

D. Both B. and C.

2773. Which of the following will give maximum gas conversion ?
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A. Plug-flow catalytic reactor

B. Fixed bed reactor

C. Semi-fluidised bed reactor

D. Fluidised bed reactor

2774. For the liquid phase parallel reactions__________________?
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A. Low temperature in a PFR

C. desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted

D. rR = K1.CA2; E1 = 80 KJ/mole

E. High temperature in a CSTR

F. High temperature in a PFR
2781. Which of the following curves shows the effect of temperature on the extent of gas-solid adsorption at a given pressure ?
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A. Langmuir adsorption isotherm

B. None of these

C. Adsorption isobar

D. Freundlich adsorption isotherm

2783. Which of the following is not a theory of homogeneous reaction ?
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A. None of these

B. Radiation hypothesis

C. Chain reaction theory

D. Collision theory and activated complex theory

2786. A rise in temperature ______________________?
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A. Does not affect photo-chemical reaction rates

B. Does not affect a catalysed reaction

C. All A., B. and C.

D. Normally tends to increase the reaction rate

2787. The reactions with low activation energy are _____________________?
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A. Slow

B. Fast

C. Non-spontaneous

D. Always spontaneous

2788. The reaction rate almost gets doubled for 10C rise in temperature. This is due to the fact that the_________________?
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A. Increased temperature reduces the activation energy

B. Value of threshold energy decreases

C. Fraction of molecules having threshold energy increases

D. Collision frequency increases

2789. Photo-chemical reactions occur in presence of ___________________?
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A. Solid catalysts

B. Sunlight

C. Darkness

D. Monochromatic radiation only

2791. For an autocatalytic reactor, the suitable reactor set up is__________________?
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A. CSTR in series

B. P.F. reactors in series

C. P.F. reactor followed by CSTR

D. CSTR followed by P.F. reactor
2793. Bulk diffusion in catalyst pore _______________ with increase in pressure?
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A. Increases

B. Increases exponentially

C. Remains unchanged

D. Decreases
2794. 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 in initial concentration of A

C. Decrease of temperature

D. Increase of temperature
2798. If n is the order of reaction, then unit of rate constant is _________________?
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A. 1/(time)(concentration)n 1

B. None of these

C. (Time)-1 (concentration)n 1

D. (Time)n 1 (concentration)

2800. According to the law of mass action, the rate of reaction is directly proportional to the__________________?
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A. Nature of the reactants

B. Volume of the reaction vessel

C. Molar concentration of the reactants

D. Equilibrium constant