Competitive Chemical Reaction MCQs – Most Latest Chemical Engineering MCQs

Competitive Chemical Reaction MCQs – Most Latest Chemical Engineering MCQs

This post is comprising of latest ” Chemical Reaction MCQs – Latest Competitive Chemical Engineering MCQs “. Here you’ll get latest mechanical engineering mcqs for written test, interview with answers. If you want to improve your knowledge regarding mechanical engineering then read these mcqs of Design of Steel Structures.

Latest Chemical Engineering MCQs

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Latest Chemical Reaction Mcqs

The most occurred mcqs of Chemical Reaction in past papers. Past papers of Chemical Reaction Mcqs. Past papers of Chemical Reaction Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Chemical Reaction Mcqs. The Important series of Chemical Reaction Mcqs are given below:

A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be ____________________ minutes?

A. 8
B. 4
C. 12
D. 16

The minimum energy required to allow a chemical reaction to proceed is termed as the ‘threshold energy ‘. Chemical reactions with low activation energy are ________________?

A. Mostly irreversible
B. Insensitive to temperature changes
C. Always irreversible
D. Highly temperature sensitive

Which of the following resistances is not involved in a gas phase catalytic (gas-solid) reaction ?

A. Ash resistance
B. Surface phenomenon resistance
C. Gas film and pore surface diffusion resistances for reactants
D. Gas film and pore surface diffusion resistances for products

For every 10°C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70°C, the rate of reaction increases ______________ times?

A. 12
B. 8
C. 16
D. 32

For the non catalytic reaction of particles with surrounding fluid, the same needed to achieve the same fractional conversion for particles of different unchanging sizes is proportional to the particle diameter, when the ________________ is the controlling resistance?

A. Diffusion through ash layer
B. Film diffusion
C. Chemical reaction
D. Either A., B. or C.

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)) ?

A. 500
B. 400
C. 600
D. 1000

A space velocity of 5 hr-1 means that ___________________?

A. Five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour
B. Cent per cent conversion can be achieved in at least 5 hours
C. After every 5 hours, reactor is being filled with the feed
D. A fixed conversion of a given batch of feed takes 5 hours

Maximum equilibrium conversion for endothermic reaction is obtained at the ______________ temperature?

A. Highest possible
B. Intermediate
C. Lowest possible
D. Room

The order of the chemical reaction as shown in the bellow figure, whose rate equation is given as -rA = KCA_________________?

2. CB is
A. 1
B. 0
C. 2
D. 3

For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant ?

A. Decreases with pressure
B. Increases with pressure
C. Is independent of pressure
D. Increases /decreases with pressure depending on the stoichiometric co-efficients of the reaction

Collision theory gives the rate constant for bimolecular reaction as___________________?

A. K α eE/RT
B. K α √T.e-E/RT
C. K α e-E/RT
D. None of these

What is the order of a chemical reaction in which doubling the initial concentration of the reactants doubles the half life time of the reaction ?

A. 0
B. 2
C. 1
D. 3

Which of the following is a characteristic of an ideal plug flow reactor ?

A. Uniform mixing
B. Flat velocity profile
C. Axial dispersion
D. None of these

For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?

A. -ln(1 – XA) = kt
B. [CA0/(1 + εA XA)] (dXA/dt) = k
C. XA = k . t
D. εA . ln (1 – XA) = k . t

If the rate of a chemical reaction becomes slower at a given temperature, then the__________________?

A. Initial concentration of the reactants remains constant
B. Entropy changes
C. Free energy of activation is lower
D. Free energy of activation is higher

With increase in the space time of an irreversible isothermal reaction being carried out in a P.F. reactor, the conversion will________________?

A. Increase
B. Remain same
C. Decrease
D. Data in insufficient; can’t be predicted

Helium-mercury method is used for the measurement of the ________________ of the catalyst?

A. Surface area
B. Pore volume
C. Porosity
D. Both B. & C.

When a high liquid hold up is required in a reactor for gas liquid reaction, use ______________ column?

A. Packed
B. Tray
C. Spray
D. Bubble

For any reaction, we may write conversion as a function of______________________?

A. Temperature
B. Time
C. Concentration
D. All A., B. & C.

The rate at which a chemical substance reacts is proportional to its____________________?

A. Active mass
B. Molecular weight
C. Equivalent weight
D. None of these

Chemical Heat Transfer Mcqs

For the gaseous reaction 2A → B, where the feed consists of 50 mole % A and 50 mole % inerts, the expansion factor is___________________?

A. -0.5
B. 1
C. -0.25
D. 0

Organic catalysts differ from the inorganic catalyst in the sense that the former is________________?

A. Prohibitively costly
B. Active at cryogenic temperatures only
C. Proteinous in nature
D. Active at very high temperature only

For the liquid phase parallel reactions__________________?


A. High temperature in a CSTR
B. Low temperature in a CSTR
C. Low temperature in a PFR
D. High temperature in a PFR

The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is _____________________ that of mixed reactor?

A. Equal to
B. Greater than
C. Smaller than
D. Unpredictable from the data

The reaction rate constants at two different temperatures T1 and T2 are related by _________________?

A. exp (k2/k1) = (E/R) (1/T2 – 1/T1)
B. ln (k2/k1) = (E/R) (1/T1 – 1/T2)
C. ln (k2/k1) = (E/R) (1/T2 – 1/T1)
D. exp (k2/k1) = (E/R) (1/T1 – 1/T2)

For the reaction, A + B → 2B + C,___________________?

A. rA = 2rB
B. rA = -rB
C. rA = rB
D. rA = rB/2

What is the order of chemical reaction as shown in the bellow figure, if it is found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B were doubled and quadrupled when the concentrations of both B & C were doubled ?

A. 3
B. 2
C. 1
D. 4

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 ?

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

With an increase in pressure in gaseous phase chemical reactions, the fractional conversion ______________ when the number of moles decreases?

A. Increases
B. Remain unaffected
C. Decreases
D. Unpredictable from the data

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 ?

A. First order
B. Zeroth order
C. Second order
D. Third order

According to the ‘law of mass action’, the rate of reaction is directly proportional to the__________________?

A. Volume of the reaction vessel
B. Equilibrium constant
C. Nature of the reactants
D. Molar concentration of the reactants

A chemical reaction is of zero order, when the reaction rate is (where, CA = concentration of reactant) ?

A. ∝ 1/CA
B. ∝ CA
C. Independent of temperature
D. None of these

Which of the following is used for calcination of limestone and dolomite in industrial practice?

A. Fixed bed reactor
B. Moving bed reactor
C. Fluidised bed reactor
D. None of these

A first order irreversible reaction, A → B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that _____________ in the two reactors?

A. Both the conversion as well as concentrations will be different
B. Conversion in both will be the same but concentrations will be different
C. Both conversion as well as concentration are same
D. None of these

Fractional conversion _____________ with increase in pressure for ammonia synthesis reaction i.e., N2 + 3H2 ⇌ 2NH3?

A. Increases
B. Remains unchanged
C. Decreases
D. Unpredictable from the data

For the irreversible elementary reactions in parallel as shown in the bellow figure, the rate of disappearance of ‘X’ is equal to_______________?

A. CA (K1 + K2)
B. CA (K1 + K2)/2
C. CA . K2/2
D. CA . K1/2

Threshold energy in a reaction is equal to the_________________?

A. Normal energy of reactants
B. Activation energy
C. Sum of A. & B.
D. Neither A. nor B.

Which of the following will give maximum gas conversion ?

A. Fluidised bed reactor
B. Fixed bed reactor
C. Semi-fluidised bed reactor
D. Plug-flow catalytic reactor

A first order homogeneous reaction of the type X → Y → Z (consecutive reaction) is carried out in a CSTR. Which of the following curves respectively show the variation of the concentration of X, Y and Z with time ?

A. III, I, II
B. III, II, I
C. I, II, III
D. II, III, I

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

A. Series
B. Parallel
C. Series-parallel
D. None of these

In Langmuir treatment of adsorption,_________________?

A. Extent of adsorption is more than one complete monomolecular layer on the surface
B. Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect on the rate of adsorption per site
C. All the adsorption does not take place by the same mechanism
D. Whole surface of the catalyst does not have the same activity for adsorption and there is attraction between the adsorbed molecule

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_______________?

A. 7
B. 3
C. 6
D. 7/3

Equilibrium of a chemical reaction as viewed by kinetics is a ______________ state?

A. Dynamic steady
B. Dynamic unsteady
C. Static steady
D. None of these

Kinetics of a catalytic reaction can be best studied on a/an ______________ reactor?

A. Differential (flow)
B. Integral (plug flow)
C. Mixed
D. Either A., B. and C.

Chemical Engineering Basics Mcqs

In a continuous flow stirred tank reactor, the composition of the exit stream_________________?

A. Is same as that in the reactor
B. Depends upon the flow rate of inlet stream
C. Is different than that in the reactor
D. None of these

Rate of a gaseous phase reaction is given by the reaction shown in the bellow figure. The unit of rate constant is__________________?

A. (hr)-1
B. (atm)-1
C. (atm)-1.(hr)-1
D. atm.(hr)-1

Half life period of a chemical reaction is_________________?

A. The time required to reduce the concentration of the reacting substance to half its initial value
B. Half of the residence time of a reaction
C. Half of the space time of a reaction
D. None of these

Which of the following is the most suitable for very high pressure gas phase reaction ?

A. Stirred tank reactor
B. Tubular flow reactor
C. Batch reactor
D. Fluidised bed reactor

Helium-mercury method can be used to determine the _____________ of the catalyst particle?

A. Solid density
B. Pore volume
C. Porosity
D. All A., B., & C.

In a consecutive reaction system of the given figure bellow, when E1 is much greater than E2, the yield of B increases with the____________________?

A. Increase of temperature
B. Increase in initial concentration of A
C. Decrease of temperature
D. Decrease in initial concentration of A

The increase in the rate of reaction with temperature is due to__________________?

A. Increase in the average kinetic energy of the reacting molecules
B. Decrease in activation energy
C. Increase in the number of effective collisions
D. None of these

A back mix reactor is___________________?

A. Ideal at very low conversion
B. Suitable for gas phase reactions
C. Same as plug flow reactor (PFR)
D. Same as ideal stirred tank reactor

Rate constant ‘k’ and absolute temperature ‘T’ are related by collision theory (for bimolecular) as______________________?

A. k ∝ T
B. k ∝ exp(-E/RT)
C. k ∝ √T
D. k ∝ T1.5

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 _______________?

A. Two
B. One
C. Zero
D. Three

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 ___________________?

A. √m
B. 1/m
C. m
D. m2

The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the _______________ energy?

A. Activation
B. Binding
C. Potential
D. Threshold

The following half life data are available for the irreversible liquid phase reaction A → products. The overall order of reaction is __________________?

A. 1
B. 0.5
C. 1.5
D. 2

A catalyst is said to be a negative catalyst, if it ___________________?

A. Retards the rate of reaction
B. Does not initiate the reaction
C. Reduces the value of equilibrium constant
D. All A., B. and C.

For multiple reactions, the flow pattern within the vessel affects the ____________________?

A. Distribution of reaction products
B. Size requirement
C. Both A. and B.
D. Neither A. nor B.

The irreversible reaction is a special case of reversible reaction, if the________________?

A. Conversion of the reactant at equilibrium condition is zero
B. Equilibrium constant is 1
C. Reactant concentration at equilibrium condition is zero
D. All A., B. and C.

Rate of a chemical reaction is not influenced by the__________________?

A. Temperature
B. Catalyst
C. Reactants concentration
D. Number of molecules of reactants taking part in a reaction

If Thiele modulus is ________________, then the pore diffusion resistance in a catalyst may be considered as negligible?

A. ∞
B. 0
C. < 0.5
D. > 0.5

______________ explains the mechanism of catalysis?

A. Activated complex theory
B. Thermodynamics
C. Collision theory
D. None of these

Which of the following factors control the design of a fluid-solid reactor ?

A. Size distribution of solids being treated
B. Reaction kinetics for single particle
C. Flow patterns of solids and fluid in the reactor
D. All A., B. and C.

For an autocatalytic reactor, the suitable reactor set up is__________________?

A. CSTR in series
B. P.F. reactors in series
C. CSTR followed by P.F. reactor
D. P.F. reactor followed by CSTR

A reactor is generally termed as an autoclave, when it is a_____________________?

A. High pressure batch reactor
B. High pressure tubular reactor
C. Atmospheric pressure tank reactor
D. Atmospheric pressure CSTR

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 ?

A. t ∝ an
B. t ∝ 1/an – 1
C. t ∝ 1/an + 1
D. t ∝ 1/an

A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type, A → R, is taking place. The reactor is to be provided with a jacket in which coolant is flowing. Following data is given: CA0= 5 kmole/m3; XA = 0.5; Feed temperature = reactor temperature = 40°C. Rate constant at 40°C = 1 min-1; (ΔH) = – 40kJ/mole; ρ = 1000kg/m3 CP = 4 J/gm.°C ; q = 10-3 m3/min (ρ and CP are same for the reactant and product streams). The amount of heat to be removed is_________________?

A. 1 kW
B. 2/3 kW
C. 5/3 kW
D. 4 kW

For a reaction of the type of bellow given figure, the rate of reaction (- rx) is given by___________________?

A. (K1 + K2+K3) CX
B. (K1 + K1) CX
C. K1CV – K2CX
D. (K1 – K2) CX

A space time of 3 hours for a flow reactor means that___________________?

A. The time required to process one reactor volume of feed (measured at specified conditions) is 3 hours
B. Conversion is cent per cent after three hours
C. It takes three hours to dump the entire volume of the reactor with feed
D. Three reactor volumes of feed can be processed every hour

With increase in K2/K1 in case of a unimolecular type elementary reactions as shown in the bellow figure, the fractional yield of ‘R’ in mixed reactor (for a given conversion of ‘A’) ?

A. Decreases
B. Increases linearly
C. Increases
D. Remain same

For a first order reaction carried out in a plug flow reactor, the space time is__________________?

A. (1/k) ln C0/C
B. k ln C0/C
C. (1/k) ln C/C0
D. k ln C/C0

If helium is introduced in a reactor containing O2, SO2 and SO3 at equilibrium, so that total pressure increases while volume and temperature remains constant. In this case the dissociation of SO3 (as per Le Chatelier’s principle)?

A. Decreases
B. Remains unaltered
C. Increases
D. Changes unpredictably

Chemical reaction rate of a component depends upon the______________________?

A. Temperature of the system
B. Composition of the component only
C. Pressure of the system
D. All A., B. and C.

Chemical Reaction Mcqs

Space time equals the mean residence time__________________?

A. When the density of the reaction mixture is constant
B. For narrow diameter tubular reactor
C. For large diameter tubular reactor
D. For CSTR

The ratio of moles of a reactant converted into the desired product to that converted into unwanted product is called_________________?

A. Relative yield
B. Operational yield
C. Selectivity
D. None of these

The unit of frequency factor in Arrhenius equation is_______________?

A. Same as that of rate constant
B. Dimensionless
C. Same as that of activation energy
D. None of these

From collision theory, the reaction rate constant is proportional to_________________?

A. exp (-E/2RT)
B. exp (-E/RT)
C. √T
D. Tm exp (-E/RT)

The synthesis of proteins and metabolism in biological objects occur in the presence of biocatalyst called_________________?

A. Haemoglobin
B. A ferment or an enzyme
C. Fungi
D. None of these

In case of a/an ______________ chemical reaction, conversion increases with the rise in temperature?

A. Irreversible exothermic
B. Reversible exothermic
C. Irreversible endothermic
D. Reversible endothermic

Transition state theory gives the rate constant as__________________?

A. K α eE/RT
B. K α e-E/RT
C. K α T . e-E/RT
D. K α √T . e-E/RT

What is the dispersion number for a plug flow reactor ?

A. 0
B. 1
C. ∞
D. -1

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___________________?

A. Zero order & K1/K2
B. First order & K1
C. Zero order & K1
D. First order & K1/K2

The rate of the heterogeneous catalytic reaction A(g) + B(g) → C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?

A. Surface reaction between absorbed A and absorbed B
B. Absorption of A
C. Surface reaction between absorbed A and B in the gas phase
D. Surface reaction between A in the gas phase and absorbed B

With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion)?

A. Increases
B. Remain same
C. Decreases
D. Increases linearly

For a mixed flow reactor operating at steady state, the rate of reaction is given by______________?

A. (FA0/V) – (dCA/dt)
B. -(dCA/dt)
C. (FA0/V) XA
D. (FA0/V) + (dCA/dt)

A Catalyst ____________________?

A. Changes the equilibrium constant of the reaction
B. Increases the equilibrium concentration of the product
C. Shortens the time to reach the equilibrium
D. None of these

The conversion in a mixed reactor/accomplishing a reaction A → 3R is 50% when gaseous reactant ‘A’ is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is _______________ second?

A. 0.5
B. 2
C. 1
D. 3

Reactions with high activation energy are_____________________?

A. Very temperature sensitive
B. Always irreversible
C. Temperature insensitive
D. Always reversible

When an exothermic reversible reaction is conducted adiabatically, the rate of reaction____________________?

A. Continuously decreases
B. Continuously increases
C. Passes through a maximum
D. Passes through a minimum

If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to___________________?

A. (E + ED)/2
B. (E + ED) where ED is activation due to diffusion
C. The intrinsic activation energy E
D. ED/2

In a/an _____________ vessel, the fluid enters and leaves following plug flow?

A. Open-closed
B. Closed
C. Open
D. Close-opened

In which of the following gaseous phase reversible reactions, the product yield cannot be increased by the application of high pressure ?

A. N2 + O2 ⇌ 2NO
B. N + 3H2 ⇌ 2NH3
C. PCl3 + Cl2 ⇌ PCl5
D. 2SO2 + O2 ⇌ 2SO3

The eddy diffusivity for a liquid in plug flow must be_________________?

A. ∞
B. 0
C. 1
D. Between 0 and 1

Reaction of benzene with chlorine gas to produce tri-chlorobenzene exemplifies a/an ______________ reaction?

A. Parallel
B. Elementary
C. Consecutive
D. None of these

Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the ___________________?

A. Activation energy
B. Heat of reaction
C. Equilibrium constant
D. None of these

In case of a _____________ reactor, the composition in the reactor and at the exit of the reactor is the same ?

A. Tubular
B. Semi-batch
C. Batch
D. Back-mix

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?

A. Increase
B. Decrease
C. No change
D. Either A. or B., depends on the type of reaction

Half-life period for a first order reaction is _____________ the initial concentration of the reactant?

A. Inversely proportional to
B. Directly proportional to
C. Independent of
D. None of these

In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for________________?

A. Fast reaction in catalyst of large pore diameter
B. Fast reactions in catalyst of small pore diameter
C. Slow reactions in catalyst of small pore diameter
D. Slow reactions in catalyst of large pore diameter

Competitive Chemical Reaction MCQs – Most Latest Chemical Engineering MCQs

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