Chemical Engineering MCQs – Chemical Reaction MCQs Latest
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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:
With decrease in temperature, the equilibrium conversion of a reversible endothermic reaction_________________?
A. Decreases
B. Remain unaffected
C. Increases
D. Increases linearly with temperature
Ionic reactions occur in____________________?
A. Liquid state only
B. Solid state only
C. Solutions
D. Any state
Enzymes are destroyed, when the_______________?
A. Temperature is very high
B. Reactant’s concentration is very low
C. Reactant’s concentration is very high
D. Reaction rate is independent of the reactant’s concentration
‘N’ plug flow reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for _______________ order reactions?
A. Second
B. First
C. Third
D. Any
______________ is the response curve for a step input signal from a reactor ?
A. I-curve
B. C-curve
C. S-curve
D. None of these
An imbalanced chemical reaction equation is against the law of________________?
A. Constant proportion
B. Conservation of mass
C. Multiple proportion
D. None of these
For a zero order chemical reaction, the__________________?
A. Plot of products concentration with time is a straight line through the origin
B. Half life period is directly proportion to the initial concentration of the reactants
C. Products concentration increases linearly with time
D. All A., B. and C.
Which of the following is a controlling factor in very fast heterogeneous reaction ?
A. Heat and mass transfer effects
B. Temperature
C. Pressure
D. Composition of reactant
In case of physical adsorption, the heat of adsorption is of the order of _____________ kcal/kg mole?
A. 10000
B. 1000
C. 100
D. 100000
In the reversible reaction of the type, A + B ⇌ AB, in general__________________?
A. Neither of the reactions will be endothermic
B. Both forward and backward reactions will be exothermic
C. The combination reaction will be exothermic, while the dissociation reaction will be endothermic
D. The combination reaction will be endothermic, while the dissociation reaction will be exothermic
For a solid catalysed chemical reaction, the effectiveness of solid catalyst depends upon the ______________ adsorption?
A. Physical
B. Chemical
C. Both of the above
D. Neither of the above
A backmix reactor_________________?
A. Employs mixing in axial direction only
B. Is same as ideal stirred tank reactor
C. Is same as plug-flow reactor
D. Is most suitable for gas phase reaction
A batch reactor is suitable for__________________?
A. Achieving cent percent conversion of reactants into products
B. Obtaining uniform polymerisation products in highly exothermic reactions
C. Liquid phase reactions
D. Large scale gaseous phase reactions
Chemical Engineering Basics Mcqs
Photochemical reaction rate does not depend significantly on temperature, because____________________?
A. It is an exothermic reaction
B. It is a reversible reaction
C. The energy of reacting molecules exceeds the activation energy by absorption of light
D. None of these
The single parameter model proposed for describing non-ideal flow is the ____________ model?
A. Dispersion
B. Tank in series
C. Both A. & B.
D. Neither A. nor B.
Radioactive decay follows ______________ order kinetics?
A. First
B. Third
C. Second
D. Zero
A batch reactor is_______________?
A. Least expensive to operate for a given rate
B. Suitable for liquid phase reactions involving small production rate
C. Suitable for gas-phase reactions on commercial scale
D. Most suitable for very large production rate
A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length ?
A. Increases
B. Decreases
C. Is at the highest allowable temperature throughout
D. First increases and then decreases
Sometimes, batch process is preferred over continuous process, when the product___________________?
A. Sales demand is fluctuating
B. Quality & yield cannot be achieved in continuous processes, because of long residence time
C. Both A. & B.
D. Neither A. nor B.
For high conversion in a highly exothermic solid catalysed reaction, use a ______________ bed reactor?
A. Fluidised
B. Fluidised bed reactor followed by a fixed
C. Fixed bed reactor followed by a fluidised
D. Fixed
A photochemical reaction is _______________?
A. Catalysed by light
B. Accompanied with emission of light
C. Initiated by light
D. All A., B. & C.
For an isothermal second order aqueous phase reaction, A → B, the ratio of the time required for 90% conversion to the time required for 45% conversion is____________________?
A. 4
B. 2
C. 11
D. 22
For a heterogeneous catalytic reaction____________________?
A. Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction
B. The surface of the catalyst does not play an important role during reaction
C. The catalyst does not form an intermediate complex with the reactant
D. A relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important
In the gaseous phase ammonia formation reaction (N2 + 3H2 ⇌ 2NH3), the value of the equilibrium constant depends on the_________________?
A. Volume of the reactor
B. Total pressure of the system
C. Temperature
D. Initial concentration of N2 and H2
Reaction rate equation for the bellow figure reaction, If S at is present in large excess, what is the order of this reaction ?
A. Two
B. One
C. Zero
D. Three
The rate controlling step for the heterogeneous irreversible catalytic reaction A(g) + B(g) → C(g) is the surface reaction of absorbed A with absorbed B to give adsorbed C. The rate expression for this reaction can then be written as (where, KA, KB and KC are the equilibrium constants and is the rate constant of the rate controlling step) ?
A. k KAKB pApB / (1 + KApA + KBpB)
B. k KA pApB / (1 + KApA + KBpB)
C. k KAKB pApB / (1 + KApA + KBpB + KCpC)
D. k KAKB pApB / (1 + KApA + KBpB + KCpC)2
A catalyst______________________?
A. Cannot be recovered chemically unchanged at the end of a chemical reaction
B. Lowers the activation energy of reacting molecules
C. Is capable of reacting with any one of the reactants
D. Initiates a reaction
The reason why a catalyst increases the rate of reaction is that, it______________?
A. Decreases the energy barrier for reaction
B. Decreases the molecular collision diameter
C. Increases the activation energy
D. None of these
The half life period of a first order reaction is given by (where, K = rate constant) ?
A. 2.5 K
B. 1.5 K
C. 0.693/K
D. 6.93 K
BET apparatus_______________________?
A. Measures the catalyst surface area directly
B. Is made entirely of stainless steel
C. Operates at very high pressure
D. None of these
In an exothermic chemical reaction, the reactants compared to the products have__________________?
A. Less energy
B. More energy
C. Higher temperature
D. Same energy
If CA is the quantity of reactants initially present, the quantity left after ‘n’ half periods will be equal to__________________?
A. (CA/2)1/n
B. (½)n CA
C. (CA/2)n
D. (CA)1/2n
The rate constant of a chemical reaction decreases by decreasing the____________________?
A. Concentration of reactants
B. Pressure
C. Temperature
D. Duration of reaction
For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of ‘P’ is doubled. If the reaction rate is proportional to Cp n, then what is the value of ‘n’ for this chemical reaction ?
A. 2
B. 1
C. 0
D. 3
The fractional volume change of the system for the isothermal gas phase reaction, A → 3B, between no conversion and complete conversion is___________________?
A. 1
B. 0.5
C. 2
D. 3
Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments where the ratio of concentration of B to that of A in the initial feed was less than 0.5, the concentration of B increased first, reached a maximum and then declined with time. However, for all experiments where this concentration ratio was 0.5 or above, concentration of B decreased monotonically with time right from the beginning. What is the ratio of the two rate constants (k1/k2) ?
A. 1/4
B. 2
C. 1/2
D. 4
The dimensions of rate constant for reaction 3A → B are (l/gm mole)/min. Therefore the reaction order is______________________?
A. 1
B. 0
C. 2
D. 3
Transition state theory relates the above quantities as___________________?
A. k ∝ √T
B. k ∝ T.eE/RT
C. k ∝ e-E/RT
D. k ∝ T1.5
Chemical Heat Transfer Mcqs
A catalyst loses its activity due to__________________?
A. Loss in surface area of the active component
B. Covering of the catalytic active sites by a foreign substance
C. Agglomeration of metal particles caused by thermal sintering of the solid surface
D. All A., B. and C.
In a semi-batch reactor __________________?
A. Residence time is constant
B. Velocity of reaction can be controlled
C. Condition similar to plug flow reactor exists
D. Mixing takes place in axial direction only
‘If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process’. The diffusivity under this condition is called ‘Knudsen diffusivity’, which is affected by the_____________________?
A. Pressure
B. Temperature
C. Both of the above
D. Neither of the above
Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene: 95 kmole / hr, water vapour: 97.5 k mole / hr and diethyl ether: 2.5 kmole/hr. The reactions occuring can be represented by: C2H5OH → C2H4 + H2O 2C2H5OH → C2H5 – O – C2H5 + H2O The percent conversion of ethanol in the reactor is________________?
A. 100
B. 95
C. 97.5
D. 2.5
The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is________________________?
A. Backmix reactor
B. Series of CSTR
C. Plug flow reactor
D. PFR in series
A batch adiabatic reactor at an initial temperature of 373°K is being used for the reaction, A → B. Assume the heat of reaction is – 1kJ/mole at 373°K and heat capacity of both A and B to be constant and equal to 50J/mole.K. The temperature rise after a conversion of 0.5 will be ____________?
A. 20°C
B. 10°C
C. 5°C
D. 100°C
From among the following, choose one which is not an exothermic process ?
A. Ammonia synthesis
B. Catalytic cracking
C. Methanol synthesis
D. Oxidation of sulphur
Velocity of a reaction depends upon the_________________?
A. Concentration of the reactants
B. Nature of the reactants
C. Temperature at which the reaction is carried
D. All A., B. and C.
If the time required to complete a definite fraction of reaction varies inversely as the concentration of the reactants, then the order of reaction is________________?
A. 3
B. 2
C. 1
D. 4
A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?
A. Inner catalyst core of radius R/8 does not participate in reaction
B. Inner catalyst core of radius R/2 does not participate in reaction
C. Effectiveness factor for a zero order reaction cannot be 7/8 as it must always be 1
D. Inner catalyst core of radius 7R/8 does not participate in reaction
Specific rate constant for a second order reaction__________________?
A. Is independent of temperature
B. Depends on the nature of the reactants
C. Varies with temperature
D. Both B. and C.
There is no correspondence between stoichiometric and the rate equation in case of a/an _____________ reaction?
A. Multiple
B. Elementary
C. Autocatalytic
D. Non-elementary
Pick out the wrong statement ?
A. A flat velocity profile exists in a plug flow reactor
B. Chemical reactions with high activation energy are very temperature sensitive
C. The residence time for all the elements of fluid in case of a P.F.R. need not be same
D. Half life of a reaction increases with increased initial concentration for reaction orders more than one
Pick out the correct statement?
A. Reactions with high activation energies are very temperature sensitive
B. A photochemical reaction is catalysed by light
C. Chemical equilibrium is a static state
D. A chemical reaction occurs when the energy of the reacting molecule is less than the activation energy of the reaction
Pick out the wrong statement?
A. The differential method of analysing kinetic data requires more accurate or larger amounts of data
B. The integral method of analysing kinetic data is used when the data is scattered
C. When the reaction rate is independent of temperature, the reaction is said to be of zero order
D. The ratio of volumes of plug flow reactor to that of mixed reactor is always less than one for identical feed composition, flow rate, conversion and for all positive reaction orders
Pick out the wrong statement ?
A. In a semi-batch reactor, one reactant is charged batch wise, while the other reactant is fed continuously
B. In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time
C. In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system
D. In a continuous flow reactor, both the reactants and the products flow out continuously
Pick out the correct statement?
A. A lower temperature favours the reaction of lower activation energy
B. The dispersion number for a reactor/vessel is uL/D
C. Pore volume and porosity of a catalyst is measured by Brunauer-Emmett-Teller (BET) technique
D. The rate controlling step in a reaction involving many steps is the fastest step
Pick out the wrong statement?
A. Non-ideal flow takes place in reactors due to recycling, channeling or by creation of stagnant regions
B. A very high value of equilibrium constant, K (K >> 1) indicates that the reaction is practically irreversible in nature
C. The intercept of the Arrhenius plot is called the ‘activation energy’
D. A particular chemical reaction is more temperature sensitive at low temperatures
Pick out the wrong statement?
A. Alumina is added as a promoter to iron catalyst in ammonia synthesis reaction
B. Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition
C. Activation energy for a reaction is obtained from the intercept of the Arrhenius plot
D. Presence of inerts affects the equilibrium conversion of
Pick out the wrong statement?
A. Chemisorption studies are useful in the determination of catalyst surface area and pore size distribution
B. Exit age description function E. and internal age distribution function (I) are related as, E = -(dI/dθ)
C. A higher temperature favours the reaction of higher activation energy
D. A catalyst increases the potential energy barrier over which the reactants must pass to form products
Chemical Reaction Mcqs
Pick out the wrong statement ?
A. Space time in a flow reactor is a measure of its capacity and is equal to the residence time when the density of reaction mixture is constant
B. The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively
C. Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty
D. In an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in longitudinal direction
Pick out the wrong statement?
A. Most of the enzyme catalysed reactions involve at least two substrates
B. Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C
C. Enzymes help in increasing the activation energy of the reaction
D. Equilibrium concentrations in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & products
Pick out the correct statement?
A. In catalytic reactions, the catalyst reacts with the reactants
B. A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction
C. A catalyst lowers the activation energy of the reacting molecules
D. A catalyst initiates a chemical reaction
Pick out the wrong statement pertaining to space velocity of flow reactors?
A. The space velocity of 3 hr-1 means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour
B. The unit of space velocity is (time)-1
C. The space velocity of 3 hr-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor
D. None of these
Pick out the wrong statement ?
A. Study of non-ideal flow reactor is done experimentally by stimulus-response technique
B. ‘Hold back’ is defined as the fraction of material that stays longer than the mean residence time
C. For studying a chemical reaction, it is desirable to monitor the reactants during initial stages and the products during the final stages of reaction
D. A batch reactor cannot be used to study the kinetics of catalytic reaction
Pick out the wrong statement?
A. If the rate of an irreversible reaction, A + B → 2C is k.CA.CB, then the reaction is always elementary
B. Transition state theory approaches the problem of calculating reaction rates by concentrating on the idea of activated complexes
C. According to the penetration theory, the mass transfer co-efficient decreases, if the exposure time of an eddy to the solute decreases
D. In a first order reaction, A → products; the reaction becomes slower as it proceeds, because the concentration of A decreases and the rate is proportional to the concentration of A
Pick out the wrong statement ?
A. A catalyst is specific in reaction
B. A catalyst initiates a reaction
C. A catalyst does not alter the final position of equilibrium in a reversible reaction
D. A catalyst remains unchanged in chemical composition at the end the reaction
Pick out the wrong statement ?
A. For a second order reaction, the slope of the graph/plot between rate and (concentration) is equal to the rate constant (k)
B. The order and molecularity of a complex reaction may not be the same
C. Visible radiation provides the necessary activation energy in photochemical reactions
D. Molecularity of the reaction is always a whole number greater than zero
Pick out the wrong statement ?
A. The fractional conversion at any time is same for both the constant as well as the variable volume system in case of an irreversible unimolecular type first order reaction
B. The slowest step has the greatest influence on the overall reaction rate in case of an irreversible series reaction
C. Autocatalytic reactions are exemplified by microbial fermentation reactions
D. Hydrolysis of ester in presence of alkali or acid is a zero order reaction
Pick out the correct statement ?
A. A catalyst does not change AH of the reaction
B. Law of mass action was suggested by Le-Chatelier
C. A catalyst changes the equilibrium point
D. The difference between the energy of reactants and that of the products is the activation energy
Pick out the correct statement ?
A. A catalyst speeds up the forward reaction but slows shown the reverse reaction
B. The composition of equilibrium is changed by catalyst
C. Pressure changes do not change the equilibrium concentrations
D. Addition of catalyst changes the equilibrium constant
Pick out the correct statement ?
A. A chemical reaction accompanied by evolution of heat is called an endothermic reaction
B. A chemical reaction accompanied by absorption of heat is called an exothermic reaction
C. The rate constant for a first order reaction does not change on changing the concentration units
D. Chemical equilibrium state is dynamic in nature
Pick out the wrong statement ?
A. For the same conversion, the holding time required in a batch reactor, is always equal to the space time required in a PFR
B. Arrhenius equation describing the effect of temperature on rate constant is given by, K = A.e-Ea/RT
C. Two mixed reactors of unequal size are available for producing a specified product, formed by a homogenous second order reaction. To achieve maximum production rate, the smaller reactor should be placed in series before the larger reactor
D. The mechanism for the decomposition of CH3CHO into CH4 and CO in presence of I2 is: CH3CHO + I2 → CH3I + HI + CO; slow CH3I + HI → CH4 + I2; fast Then the rate of disappearance of CH3CHO is equal to K.CCH3I.CHI and acts as a catalyst
Pick out the wrong statement ?
A. For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity
B. Plug flow reactor (PFR) is always smaller than mixed reactor for all positive reaction orders for a particular duty
C. For an ideal mixed reactor at steady state, the exit stream has the same composition as fluid within the reactor and the space time is equivalent to holding time for constant density system
D. Reaction rate does not decrease appreciably as the reaction proceeds in case of an autocatalytic reaction