Latest Chemical Engineering MCQs – Competitive Chemical Reaction MCQs
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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:
The temperature dependence of reaction rate constant (K) by Arrhenius law is given by_______________?
A. K α e-E/RT
B. K α T . e-E/RT
C. K α eE/RT
D. K α √T . e-E/RT
Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature ?
A. Ash layer diffusion
B. Film diffusion
C. Pore diffusion
D. Chemical reaction
The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are_______________?
A. 2 & 1
B. 2 & 2
C. 11 & 2
D. 1 & 1
With increase in initial concentration, the fractional conversion of a first order reaction in a given time___________________?
A. Decreases
B. Increases
C. Remain constant
D. Unpredictable
A gaseous reactant is introduced in a mixed reactor of 3 litres volume at the rate of 1 litre/second. The space time is ______________ seconds?
A. 1/3
B. 3
C. 1
D. 32
The importance of diffusion in a catalyst are increased by ____________________?
A. Small pore diameter
B. An active surface of the catalyst
C. Large catalyst particle size
D. All A., B. and C.
In an ideal mixed reactor (at steady state), the ___________________?
A. Space time is equivalent to holding time for constant density systems
B. Exit stream has the same composition as the fluid within the reactor
C. Composition throughout the reactor remains same
D. All A., B. and C.
In a reversible reaction, a catalyst increases the rate of forward reaction__________________?
A. To a greater extent than that of the backward reaction
B. Only
C. And decreases that of the backward reaction
D. And the backward reaction equally
For an ideal plug flow reactor, the value of Peclet number is_______________?
A. 0
B. 10
C. 1
D. ∞
Carbon particles accumulated on the catalyst used in the gas oil cracking lies in the category of _____________________ poison?
A. Deposited
B. Selectivity
C. Chemisorbed
D. Stability
Which of the following factors control the deactivation of a porous catalyst pellet?
A. Pore diffusion
B. Decay reactions
C. Form of surface attack by poison
D. All A., B. and C.
An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction ?
A. Is maximum at the inlet of the reactor
B. Is maximum at the exit of the reactor
C. Goes through a minimum along the length of the reactor
D. Goes through a maximum along the length of the reactor
The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of _______________ order?
A. First
B. Zero
C. Second
D. None of these
The excess energy of the reactants required to dissociate into products is known as the ________________ energy?
A. Threshold
B. Activation
C. Thermal
D. Binding
The decomposition of A into B is represented by the exothermic reaction, A ⇌ 2B. To achieve maximum decomposition, it is desirable to carry out the reaction ?
A. At low P and high T
B. At high P and high T
C. At low P and low T
D. At high P and low T
An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation is ___________________?
A. Maximum at the inlet of the reactor
B. Maximum at the centre of the reactor
C. Maximum at the exit of the reactor
D. Constant throughout the reactor
For the chemical reaction X → Y, it is observed that, on doubling the concentration of ‘X’, the reaction rate quadruples. If the reaction rate is proportional to Cx n, then what is the value of „n‟ ?
A. 1/4
B. 16
C. 4
D. 2
Backmixing is most predominant in___________________?
A. A well stirred batch reactor
B. CSTR’s connected in series
C. A single CSTR
D. A plug-flow reactor
The experimentally determined overall order of the reaction, A + B → C + D, is two. Then the__________________?
A. Reaction is elementary with a molecularity of 2
B. Molecularity of the reaction is 2, but the reaction may not be elementary
C. Reaction is elementary but the molecularity may not be 2
D. Reaction may be elementary with molecularity of 2
Exothermic reactions are best carried out in ________________?
A. CSTR in series
B. A CSTR
C. A plug flow reactor followed by CSTR
D. CSTR followed by a plug flow reactor
The energy balance equation over a tubular reactor under transient conditions is________________?
A. An algebraic differential equation
B. An ordinary non-linear differential equation
C. A linear partial differential equation
D. A non-linear partial differential equation
The rate of reaction of a/an ______________ reaction is not affected by temperature rise ?
A. Consecutive
B. Photochemical
C. Autocatalytic
D. Zero order
A trickle bed reactor is the one, which_________________?
A. Has altogether three streams either entering or leaving
B. Processes three reactants with same flow rate
C. Processes three reactants at different flow rates
D. Employs all the three phases (i.e. solid, liquid and gas)
In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants) ?
A. N
B. A
C. A + N
D. A – N
Consider the ‘n’ th order irreversible liquid phase reaction A → B. Which one of the following plots involving half life of the reaction (t1/2) and the initial reactant concentration (CA0) gives a straight line plot ?
A. ln CA0 Vs t1/2
B. CA0 Vs t1/2
C. CA0 Vs ln t1/2
D. ln CA0 Vs ln t1/2
. In the converter of the contact process for the manufacture of H2SO4 the equilibrium conversion of SO2__________ (i) __________ with increase in temperature and __________ (ii) __________ with increase in the mole ratio of SO2 to air?
A. (i) increases (ii) increases
B. (i) decreases (ii) increases
C. (i) increases (ii) decreases
D. (i) decreases (ii) decreases
The equilibrium constant for the reversible reaction as shown in the bellow figure, is affected by the__________________?
A. Presence or absence of inerts
B. Temperature of the system
C. Pressure of the system
D. Kinetics of the reaction
When the reaction is dominated by intraparticle diffusion, the apparent order of reaction (nD) as measured is related to the true order (n) as ________________?
A. nD = (n + 1)/2
B. nD = n + 1
C. nD = n/2
D. None of these
According to Arrhenius equation of temperature dependency of rate constant for an elementary reaction _________________?
A. k ∝ T e-E/RT
B. k ∝ e-E/RT
C. k ∝ √T
D. None of these
The performance of a cascade of CSTR’s can be improved by adding__________________?
A. A P.F. reactor in parallel
B. A P.F. reactor in series
C. More CSTR’s in series
D. More CSTR’s in parallel
Pick out the wrong statement ?
A. In a multistep reaction, the slowest step is the rate determining step
B. In general, the rate of a reaction becomes triple for every 10°C rise in temperature
C. Molecularity of a reaction cannot be zero but the order of a reaction can be zero
D. Slow chemical reactions have generally high values of activation energy
An isothermal aqueous phase reversible reaction, P ⇌ R, is to be carried out in a mixed flow reactor. The reaction rate in k.mole/m3 .h is given by, r = 0.5CP – 0.125CR. A stream containing only P enters the reactor. The residence time required (in hours) for 40% conversion of P is_________________?
A. 1.33
B. 0.80
C. 1.60
D. 2.67
Which of the following chemical reactions will be favoured by low pressure ?
A. N2 + O2 ⇌ 2NO
B. N2O2 ⇌ 2NO2
C. 2HI ⇌ H2 + I2
D. None of these
Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in ___________________?
A. Intestine
B. Saliva
C. Blood
D. Gland
A balanced chemical reaction equation conforms to the law of________________?
A. Conservation of mass
B. Gaseous volumes
C. Avogadro’s hypothesis
D. None of these
Chemical Reaction Mcqs
Molecularity of a reaction__________________?
A. Is always equal to the overall order of reaction
B. Can’t have a fractional value
C. May not be equal to the order of reaction
D. Both B. and C.
A multiple reaction may be classified as a ________________ reaction?
A. Parallel or side
B. Consecutive or side
C. Mixed
D. All A., B. and C.
Consecutive reaction, as shown in the bellow figure, is characterised by __________________?
A. High exothermicity
B. Maxima in the concentration of B
C. Maxima in the concentration of C
D. Maxima in the concentration of A
Slurry reactors are characterised by the_________________?
A. Presence of two mobile phases
B. Lack of intraparticle diffusion resistance
C. Both A. and B.
D. Neither A. nor B.
The role of a catalyst in a chemical reaction is to change the__________________?
A. Equilibrium constant
B. Activation energy
C. Heat of reaction
D. Final products
The reactions of high molecularity are rare, because________________?
A. Many body collisions are not favoured energetically
B. Of low probability of many body collisions
C. Of very large activation energy of many bodies
D. Of requirement of very large concentration for such reactions
Holding time for flow reactors is _______________ the space time, for constant fluid density ?
A. Triple
B. Double
C. Equal to
D. None of these
Design of heterogamous catalytic reactor involves consideration of _______________ steps?
A. Only physical
B. Only chemical
C. Both A. & B.
D. Neither A. nor B.
Pick the WRONG design guideline for a reactor in which the reactions, A → R (desired) and A → S (undesired) are to take place. The ratio of the reaction rates is rR/rS = (k1/k2). CA a-b ?
A. Use batch reactor or plug flow reactor, when a > b
B. Avoid recycle, when a > b
C. Use high pressure and eliminate inerts, when a > b
D. Use CSTR with a high conversion, when a > b
From Arrhenius law, a plot of loge K versus 1/T gives a straight line with a slope of (-E/R). The unit of E/R is___________________?
A. k cal/°K
B. k cal
C. °K
D. k cal. °K
During manufacture of H2SO4, the oxidation of SO2 to SO3 by oxygen is an endothermic reaction. The yield of SO3 will be maximised, if the _____________________?
A. Pressure is reduced
B. Temperature is increased
C. Temperature is increased and pressure is reduced
D. Temperature is reduced and pressure is increased
An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will ______________ with decrease in space time?
A. Increase exponentially
B. Increase
C. Decrease
D. Remain unchanged
Which of the following is an autocatalytic reaction ?
A. Enzyme fermentation reaction
B. Microbial fermentation reaction
C. Photochemical reactions
D. Ammonia synthesis reaction
What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on ?
A. Litre/mole.second
B. Litre/mole
C. Moles/litre.second
D. Litre/second
With increase in temperature, the equilibrium _______________ rises in case of endothermic reaction?
A. Constant
B. Conversion
C. Both of the above
D. Neither of the above
Reverse reaction in a chemical equilibrium is favoured by the________________?
A. Increase in the concentration of one of the reactants
B. Increase in the concentration of one of the products
C. Removal of one of the products regularly
D. None of these
When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only _______________ the true value?
A. Equal
B. Half
C. Twice
D. None of these
For a first order chemical reaction, the rate constant_________________?
A. Is not a function of the unit of time
B. Changes on changing the concentration units
C. Has unit of time-1
D. None of these
The rate of forward reaction, at chemical equilibrium is ______________ the rate of backward reaction?
A. Less than
B. More than
C. Equal to
D. Either B. or C.
An exothermic reaction takes place in an adiabatic reactor. The product temperature ______________ reactor feed temperature?
A. Is always less than
B. Is always greater than
C. Is always equal to
D. May be greater or less than
Which of the following is the most suitable for isothermal operation?
A. Plug-flow reactor
B. Back-mix reactor
C. Batch reactor
D. Fixed bed reactor
The rate at which a chemical substance reacts is proportional to its _____________________?
A. Active mass
B. Equivalent weight
C. Molecular weight
D. Atomic weight
Sum of the powers of the concentration terms in the rate equation is called the _____________ of the reaction?
A. Molecularity
B. Overall order
C. Order
D. None of these
Thermodynamic equilibrium constant in a system is affected by___________________?
A. Pressure
B. Inerts
C. Temperature
D. All A., B. & C.
Considering the endothermic dissociation of CaCO3 in a closed vessel (CaCO3 ⇌ CaO + CO2), the pressure of CO2 increases, if____________________?
A. An inert gas is pumped keeping the temperature constant
B. The temperature is increased
C. A catalyst is added
D. None of these
Chemical Heat Transfer Mcqs
Conversion increases with increase in temperature in case of a/an ______________ reaction?
A. Irreversible
B. Autocatalytic
C. Reversible endothermic
D. Reversible exothermic
In case of _____________ reactions, the reaction rate does not decrease appreciably as the reaction proceeds?
A. Parallel
B. Catalytic
C. Series
D. Auto catalytic
The catalytic activity of enzymes is due to their capacity to lower the ______________ energy?
A. Activation
B. Kinetic
C. Potential
D. None of these
The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is________________?
A. 0
B. ∞
C. 1
D. > 1
A catalyst in a chemical reaction _______________ free energy change in the reaction?
A. Decreases
B. Increases
C. Either A. or B.; depends on the type of catalyst
D. Neither A. nor B.
Rate constant for a first order reaction does not depend upon reaction time, extent of reaction and the initial concentration of reactants; but it is a function of reaction temperature. In a chemical reaction, the time required to reduce the concentration of reactant from 100 gm moles/litre to 50 gm moles/litre is same as that required to reduce it from 2 gm moles/litre to 1 gm mole/litre in the same volume. Then the order of this reaction is ?
A. 2
B. 1
C. 0
D. 3
The units of frequency factor in Arrhenius equation_________________?
A. Are the same as those of the rate constant
B. Are cycles per unit time
C. Depend on temperature, pressure etc. of the reaction
D. Depend on the order of the reaction
The rate constant of a first order reaction depends on the ________________?
A. Concentration of the product
B. Temperature
C. Concentration of the reactant
D. Time
The catalyst in a second order reversible reaction increases the rate of the forward reaction___________________?
A. Only
B. And backward reaction equally
C. And decreases that of backward reaction
D. To a greater extent than that of the backward reaction
If in the gaseous phase reaction, N2O4 ⇌ 2NO2, x is the part of N2O4 which dissociates, then the number of molecules at equilibrium will be___________________?
A. (1 + x)
B. (1 + x)2
C. (1 – x)
D. (1 – x)2
____________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction ?
A. Ash diffusion
B. Gas film diffusion
C. Chemical reaction
D. None of these
Rate determining step in a reaction consisting of a number of steps in series is the ______________ step?
A. Intermediate
B. Slowest
C. Fastest
D. Data insufficient; can’t be predicted
Catalyst carriers___________________?
A. Increase the activity of a catalyst
B. Have very high selectivity
C. Provide large surface area with a small amount of active material
D. Inhibit catalyst poisoning
In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will________________?
A. Remain the same
B. Also be doubled
C. Be halved
D. Become one fourth
Chemical Engineering Basics Mcqs
Which of the following is not a chemical step in a fluid solid catalytic reaction ?
A. Adsorption
B. Surface chemical reaction
C. Desorption
D. None of these
Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as_________________?
A. DE = DM . DE
B. 1/DE = 1/DN + DK
C. DE = DM + DK
D. DE = DN/DE
At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenius law is used. What will be this ratio, if transition state theory is used with the same value of „E/R‟ ?
A. 2
B. 1.6
C. 2.24
D. 2.5
A high space velocity means that a given__________________?
A. Conversion can be obtained with a high feed rate
B. Reaction can be accomplished with small reactor
C. Both A. and B.
D. None of these
Signal normally used to study non-ideal flow by stimulus response technique is _______________ input?
A. Step
B. Pulse
C. Both A. & B.
D. Neither A. nor B.
The effect of increasing pressure on the gaseous equilibrium of the reaction 2X + 3Y ⇌ 3X + 2Y indicates that____________________?
A. Pressure has no effect
B. Forward reaction is favoured
C. Backward reaction is favoured
D. None of these
For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be ______________ times?
A. 1/8
B. 16
C. 8
D. 1/16
For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a _________________ reactor?
A. Stirred tank
B. Batch
C. Tubular flow
D. Fixed bed
When a catalyst increases the rate of forward reaction, the value of rate constant__________________?
A. Increases
B. Remain same
C. Decreases
D. Becomes infinite
In a/an ______________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation?
A. Isothermal
B. Adiabatic
C. Non-adiabatic
D. None of these
In an ideal tubular-flow reactor_________________?
A. Mixing takes place in radial direction
B. There is no mixing in longitudinal direction
C. There is a uniform velocity across the radius
D. All A., B. and C.
In flow reactors, the performance equations interrelate the rate of reaction to the___________________?
A. Reactor volume
B. Feed rate
C. Extent of reaction
D. All A., B. and C.
When all the limiting reactant is consumed in the reaction, the operational yield _______________ the relative yield?
A. Is smaller than
B. Is greater than
C. Equals
D. Can be either greater or smaller than (depends on the type of reaction)
Which of the following is an independent variable for a batch tank reactor with uniform concentration and temperature ?
A. Time
B. Diameter of the reactor
C. Useful volume of the tank
D. None of these
A reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?
A. Photochemical
B. Autocatalytic
C. Catalytic
D. None of these
When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is__________________?
A. < 1
B. > 1
C. 1
D. 0
For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min-1. What will be the conversion for a PFR with a space velocity of 0.2 min-1? Assume that all the other operating conditions are the same for CSTR and PFR ?
A. 0.30
B. 0.15
C. 0.60
D. 0.90
The rate of a chemical reaction is almost doubled for every 10°C rise in temperature. The rate will increase ______________ times, if the temperature rises from 10 to 100°C?
A. 112
B. 512
C. 256
D. 612
A first order reaction requires two unequal sized CSTR. Which of the following gives higher yield ?
A. Smaller reactor followed by larger one
B. Large reactor followed by smaller one
C. Either of the arrangement A. or B. will give the same yield
D. Data insufficient, can’t be predicted
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_________________?
A. Tubular reactor is preferred over a single CSTR for high yield
B. Batch reactor is preferred over a single CSTR for high yield
C. Both A. and B.
D. Single CSTR is the most suitable
At a given temperature, K1, K2 and K3 are equilibrium constants for the following reactions 1, 2, 3 respectively. CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g), CO(g) + H2O(g) ⇌ CO2(g) + H2(g) CH4(g) + 2H2O(g) ⇌ CO2(g) + 4H2(g) Then K1, K2 and K3 are related as ?
A. K3 = K1.K2
B. K3(K1+K2)/2
C. K3 = (K1.K2)0.5
D. K3 = (K1.K2)2
For a vapour phase catalytic reaction (A + B → P) which follows the Ridel mechanism and the reaction step is rate controlling, the rate of reaction is given by (reaction rate is irreversible, product also absorbs) ?
A. -rA = (k . PA . PB)/(1 + KAPA + KPPP)
B. -rA = (k . PA . PB)/(1 + KAPB + KBPB . KPPP)
C. -rA = (k . PA 2 – k1PP)/(1 + KAPA + KPPP)
D. -rA = (k . PA . PB)/(1 + KAPA)
Which of the following will favour the reverse reaction in a chemical equilibrium reaction ?
A. Removal of at least one of the products at regular interval
B. Increasing the concentration of one or more of the products
C. Increasing the concentration of one of the reactants
D. None of these
An autothermal reactor is_________________?
A. Most suitable for a reversible reaction
B. Most suitable for a second order reaction
C. Completely self-supporting in its thermal energy requirements
D. Isothermal in nature
Sulphuric acid is used as a catalyst in the_______________?
A. Gas phase oxidation of SO2 in chamber process
B. Hydrogenation of oils
C. Alkylation of hydrocarbons
D. None of these
In a chemical reaction, _____________________ are conserved?
A. Masses
B. Ions
C. Atoms
D. Both B. & C.