chemical engineering Mcqs
2951. Shift conversion reaction_________________?
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A. Converts CO to CO2 with steam

B. Converts N2 and H2 into NH3

C. Is non-catalytic

D. Is highly exothermic

2952. What is the value of n if the reaction rate of the chemical reaction A ? B, is proportional to CA n and it is found that the reaction rate triples, when the concentration of A is increased 9 times ?
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A. 1/2

B. 9-Jan

C. 3

D. 3-Jan

2953. Which of the following holds good for an elementary reaction as shown in the bellow figure ?
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A. The rate of disappearance of Y is equal to the rate of appearance of Z

B. Three times the rate of disappearance of X is equal to the rate of appearance of Z

C. The rate of disappearance of Y is equal to the rate of disappearance of X

D. The rate of disappearance of X is equal to the rate of appearance of Z

2954. In a chemical reaction as shown in the bellow figure, it is observed that the (i) Rate of formation of P is doubled on doubling the concentration of X (ii) Rate of formation of P is quadrupled on doubling the concentration of Y (iii) Doubling the concentration of Z does not affect the rate of formation of P What is the order of the above chemical reaction ?
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A. Zeroth order

B. First order

C. Second order

D. Third order
2955. Promoter_____________________?
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A. Initiates a chemical reaction and is a catalyst by itself

B. ating discontinuities in the crystals</strong>

C. Increases the number of active centres by increasing the unevenness of catalyst surface and by

D. All A., B. and C.

E. Alters the position of equilibrium in a reversible reaction

2956. Molecularity of an elementary reaction, P + Q ? R + S is ____________________?
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A. 1

B. 2

C. 3

D. 4
2957. Following isothermal kinetic data are obtained in a basket type of mixed flow reactor for a porous catalyst. Determine the role of pore diffusion and external mass transfer processes ?
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A. Strong pore diffusion control and mass transfer not controlling

B. Both pore diffusion and mass transfer not controlling

C. Both pore diffusion and mass transfer controlling

D. Mass transfer controlling

2958. Rate of a chemical reaction is independent of the concentration of the reactants for a _________________ reaction?
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A. Zero order

B. Consecutive

C. None of these

D. Third order

2959. A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m3 and volumetric flow rate 1m3 /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m3. The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 k.mole/m3, the volume of the mixed flow reactor should be increased by a factor of_______________?
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A. 3

B. 3-Jul

C. 6

D. 7
2960. Which of the following is used for calcination of limestone and dolomite in industrial practice?
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A. None of these

B. Fixed bed reactor

C. Fluidised bed reactor

D. Moving bed reactor
2961. _____________ gas is normally employed in B.E.T. method of finding out the surface area of catalyst?
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A. N2

B. H2

C. CO2

D. He

2962. ______________ explains the mechanism of catalysis?
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A. None of these

B. Collision theory

C. Activated complex theory

D. Thermodynamics

2963. The rate of the chemical reaction A ? B doubles as the concentration of A i.e.., CA is doubled. If rate of reaction is proportional to CA n, then what is the value of n for this reaction ?
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A. 1

B. 0

C. 0.5

D. 2

2964. A chemical reaction, A ? 3B, is conducted in a constant pressure vessel. Starting with pure A, the volume of the reaction mixture increases 3 times in 6 minutes. The fractional conversion is ___________________?
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A. 1

B. Data insufficient, cant be predicted

C. 0.5

D. 0.33

2965. The irreversible reaction is a special case of reversible reaction, if the________________?
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A. Conversion of the reactant at equilibrium condition is zero

B. Reactant concentration at equilibrium condition is zero

C. Equilibrium constant is 1

D. All A., B. and C.

2966. Which of the following is a characteristic of an ideal plug flow reactor ?
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A. Flat velocity profile

B. Axial dispersion

C. Uniform mixing

D. None of these

2967. Batch process is preferred over continuous process, when the___________________?
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A. Same equipment cannot be used for several processes of the same nature

B. idence time

C. Product yields and quality cannot be achieved in continuous process, because of long

D. All A., B. & C.

E. Sales demand of product is not steady

2968. For a tubular flow reactor with uniform concentration and temperature, the independent variable is___________________?
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A. Diameter

B. None of these

C. Length

D. Time

2969. Velocity of a chemical reaction___________________?
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A. Decreases with increase in temperature

B. None of these

C. Increases with increase of pressure of reactants for all reactions

D. Decreases with increase of reactant concentration

2970. B.E.T. method of finding out surface area of a catalyst, uses the extension of _________________ isotherm?
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A. None of these

B. Freundlich

C. Langmuir

D. Tempkin

2971. The reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?
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A. Catalytic

B. Photochemical

C. Biochemical

D. Autocatalytic
2972. A chemical reaction occurs when the energy of the reacting molecules is __________________ the activation energy of the reaction?
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A. Equal to or more than

B. More than

C. Less than

D. Equal to

2973. The preferred reacting system for oxidation of o-xylene to phthalic anhydride is _____________________?
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A. Jacketed liquid phase CSTR

B. Multistage multitubular reactor with interstage cooling

C. Multitubular reactor with cooling

D. Jacketed steam heated multitubular reactor

2974. 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. m

B. 1/m

C. ?m

D. m2

2975. The increase in the rate of reaction with temperature is due to__________________?
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A. Decrease in activation energy

B. None of these

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

D. Increase in the number of effective collisions

2976. For a homogeneous reaction of nth order, the dimension of the rate constant is given by_________________?
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A. (Concentration)1 n/(time)

B. (Concentration)n 1/(time)

C. 1/(time)n

D. None of these

2977. Most important characteristics of gas-liquid reactors are the________________?
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A. Specific inter-facial area

B. Liquid hold-up

C. Both A. and B.

D. None of these

2978. A non-catalytic chemical reaction of the type as shown in the bellow figure is called a _____________ reaction?
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A. Series

B. None of these

C. Parallel

D. Series-parallel
2979. A space velocity of 5 hr-1 means that ___________________?
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A. After every 5 hours, reactor is being filled with the feed

B. A fixed conversion of a given batch of feed takes 5 hours

C. Cent per cent conversion can be achieved in at least 5 hours

D. Five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour
2980. When a catalyst increases the rate of chemical reaction, the rate constant_____________________?
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A. Remain constant

B. Become infinite

C. Decreases

D. Increases
2981. The reaction A ? B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k) is (Data: Heat of reaction at 298 K = 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100kJ/kmole. K (may be assumed to be independent of temperature)) ?
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A. 1000

B. 400

C. 600

D. 500

2982. BET apparatus is used to determine the ___________________?
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A. Specific surface of a porous catalyst

B. Pore diameter

C. Porosity of the catalyst bed

D. Pore size distribution

2983. For a heterogeneous catalytic reaction, A + B ? C, with equimole feed of A and B, the initial rate rA0 is invariant with total pressure. The rate controlling step is______________________?
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A. Desorption of C

B. Surface reaction between A in the gas phase and absorbed B

C. Surface reaction between absorbed A and absorbed B

D. Surface Kc/(1 + TS) reaction between absorbed A and B in the gas phase

2984. The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the_________________?
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A. None of these

B. Space time for parallel lines is different

C. Larger reactors have more space time compared to smaller ones

D. Space time for each parallel line is same
2985. The reaction rate constants at two different temperatures T1 and T2 are related by _________________?
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A. exp (k2/k1) = (E/R) (1/T2 1/T1)

B. exp (k2/k1) = (E/R) (1/T1 1/T2)

C. ln (k2/k1) = (E/R) (1/T2 1/T1)

D. ln (k2/k1) = (E/R) (1/T1 1/T2)
2986. n number of plug flow reactors (P.F.R) in series with a total volume V gives the same conversion as one P.F.R. of volume________________?
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A. V/n

B. V

C. V.n

D. 1/V

2987. The rate of reaction does not decrease appreciably as the reaction proceeds in case of ______________ reactions?
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A. Endothermic

B. Autothermal

C. Autocatalytic

D. Exothermic

2988. A liquid phase reaction is to be carried out under isothermal conditions. The reaction rate as a function of conversion has been determined experimentally and is shown in the figure given below. What choice of reactor or combination of reactors will require the minimum overall reactor volume, if a conversion of 0.9 is desired ?
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A. PFR followed by a CSTR

B. CSTR followed by a PFR

C. CSTR followed by a PFR followed by a CSTR

D. PFR followed by a CSTR followed by a PFR
2989. A first order gaseous phase reaction is catalysed by a non-porous solid. The kinetic rate constant and the external mass transfer co-efficients are k and kg respectively. The effective rate constant (keff) is given by________________?
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A. 1/keff = 1/k + 1/kg

B. keff = k + kg

C. keff = (k+ kg)/2

D. keff = (kkg)1/2

2990. The following gas phase reaction is taking place in a plug flow reactor. A stoichiometric mixture of A and B at 300 K is fed to the reactor. At 1 m along the length of the reactor, the temperature is 360 K. The pressure drop is negligible and an ideal gas behaviour can be assumed. Identify the correct expression relating the concentration of A at the inlet (CA0), concentration of A at 1m (CA) and the corresponding conversion of A (X) ?
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A. CA = 0.83 CA0 (1 X)/(1 0.33X)

B. CA = 1.2 CA0 (1 X)/(1 0.5X)

C. CA = 1.2 CA0 (1 X)/(1 0.33X)

D. CA = 0.83 CA0 (1 X)/(1 0.5X)

2991. Arrhenius equation shows the variation of ___________________ with temperature?
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A. Rate constant

B. Reaction rate

C. Energy of activation

D. Frequency factor

2992. Rate of an autocatalytic chemical reaction is a function of ___________________?
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A. All A., B. and C.

B. Pressure only

C. Composition only

D. Temperature only

2993. The fractional volume change between no conversion and complete conversion, for the isothermal gas phase reaction, 2A ? R, is___________________?
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A. 0.5

B. 1.5

C. 1

D. -0.5
2994. 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. Two

B. Three

C. One

D. Zero

2995. Calcination reaction of limestone (CaCO3 ? CaO + CO2) goes to completion in the rotary kiln, because____________________?
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A. CO2 escapes continuously

B. Of high calcination temperature

C. CaO is more stable than CaCO3

D. CaO is not dissociated

2996. A catalyst inhibitor____________________?
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A. Is added in small quantity during the catalyst manufacture itself

B. May be useful for suppressing undesirable side reactions

C. All A., B. and C.

D. Lessens its selectivity

2997. The irreversible reaction, X ? Y, is the special case of the reversible reaction, X ? Y, in which the _____________________?
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A. Fractional conversion of A at equilibrium is unity

B. Concentration of A at equilibrium is zero

C. All A., B. and C.

D. Equilibrium constant is infinite

2998. The concentration of A in a first order reaction, A ? B, decreases_____________________?
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A. Linearly with time

B. Logarithmically with time

C. Exponentially with time

D. Very abruptly towards the end of the reaction

2999. Fluidised bed reactor is characterized by____________________?
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A. Absence of continuous catalyst regeneration facility

B. Uniformity of temperature

C. Comparatively smaller equipment

D. Very small pressure drop

3000. 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