Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 2

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.

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


C.

Arrehenius equation describing the effect of temperature on rate constant is given by, K = A.e-Ea/RT


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


Options are :

  • D
  • B
  • A
  • C

Answer :D

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 3

The extent of a reaction is:


Options are :

  • Dimensionless
  • All of the above
  • Depends on the stoichiometric co-efficient
  • Different for reactants and products

Answer :All of the above

Oil is hydrogenated using nickel catalyst in a __________ reactor


Options are :

  • Fixed bed
  • Fluidised bed
  • Batch
  • Slurry

Answer :Slurry

Thermodynamic equilibrium constant in a system is affected by:


Options are :

  • All of these
  • Temperature
  • Inerts
  • Pressure

Answer :Temperature

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 4

A multiple reaction may be classified as a __________ reaction


Options are :

  • Consecutive or side
  • Parallel or side
  • Mixed
  • All of these

Answer :All of these

The half life period 't' of a zero order reaction,

, is equal to:


Options are :

  • 1/K
  • 0.693/K
  • CA0/K
  • CA0/2K

Answer :CA0/2K

Pick out the correct statement:


Options are :

  • A catalyst changes the equilibrium point
  • A catalyst does not change AH of the reaction
  • The difference between the energy of reactants and that of the products is the activation energy
  • Law of mass action was suggested by Le-Chatelier

Answer :A catalyst does not change AH of the reaction

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 5

Reverse reaction in a chemical equilibrium is favoured by the:


Options are :

  • Increase in the concentration of oneof the products
  • Removal of one of the products regularly
  • Increase in the concentration of one of the reactants
  • None of these

Answer :Increase in the concentration of oneof the products

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


Options are :

  • Avoid recycle, when a > b
  • Use CSTR with a high conversion, when a > b
  • Use high pressure and eliminate inerts, when a > b
  • Use batch reactor or plug flow reactor, when a > b

Answer :Avoid recycle, when a > b

Molecularity of an elementary reaction, P + Q

R + S is:


Options are :

  • 1
  • 3
  • 4
  • 2

Answer :4

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 6

A balanced chemical reaction equation conforms to the law of:


Options are :

  • Avagadro's hypothesis
  • None of these
  • Conservation of mass
  • Gaseous volumes

Answer :Conservation of mass

Holding time for flow reactors is __________ the space time, for constant fluid density


Options are :

  • Double
  • Equal to
  • None of these
  • Triple

Answer :Equal to

A catalyst promoter:


Options are :

  • Acts as a catalyst support
  • Improves the activity of a catalyst
  • All of these
  • Itself has very high activity

Answer :Improves the activity of a catalyst

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 7

In which of the following reactions, thee-quilibrium will shift to the right, if the total pressure is increased ?


A.

H2 + Cl2

2HCl


B.

N2 + O2

2NO


C.

N2O4

2 NO2


D.

H2 + I2

2HI


Options are :

  • B
  • C
  • A
  • D

Answer :B

Reaction rate of a first order reaction, which is half completed in 23 minutes will be:


Options are :

  • 0.03 min-1
  • 0.03 hr-1
  • 0.05 min-1
  • 0.03 sec-1

Answer :0.03 min-1

Decomposition rate of a liquid 'X' which decomposes as per the reaction

is given by:


Options are :

  • (K1 + K2 + K3)CX
  • K1 . CX
  • (K1 + K2)CX
  • (K2 + K3)CX

Answer :(K1 + K2)CX

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 8

The order of the reaction,

, is:


Options are :

  • 1
  • 0
  • 2
  • 3

Answer :0

Higher free energy of activation of a chemical reaction (at a given temperature) implies:


Options are :

  • Both B and C
  • Higher equilibrium conversion
  • Slower rate of reaction
  • Higher rate of reaction

Answer :Slower rate of reaction

The energy of activation of a chemical reaction:


Options are :

  • Is the minimum energy which the molecules must have before the reaction can take place
  • Is same as heat of reaction at constant pressure
  • Varies as fifth power of the temperature
  • Both B and C

Answer :Is the minimum energy which the molecules must have before the reaction can take place

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 9

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:


Options are :

  • Gland
  • Saliva
  • Blood
  • Intestine

Answer :Saliva

Carrier in a catalyst increases its:


Options are :

  • Activity
  • Surface area
  • None of these
  • Performance

Answer :Surface area

Which of the following is not a dimension-less group used in catalysis ? (where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2/sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3/sec . V = volume, cm3.)


A.

Reactor dispersion number (D/vL)


B.

Reduced time


C.

Thiele modulus


D.

None of these


Options are :

  • A
  • C
  • D
  • B

Answer :D

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 ?


Options are :

  • CA0 Vs t1/2
  • CA0 Vs ln t1/2
  • ln CA0 Vs t1/2
  • ln CA0 Vs ln t1/2

Answer :CA0 Vs ln t1/2

The most suitable reactor for carrying out an auto-thermal reaction is a:


Options are :

  • Plug-flow reactor
  • CSTR
  • Batch reactor
  • Semi-batch reactor

Answer :CSTR

Arhenious equation shows the variation of __________ with temperature


Options are :

  • Rate constant
  • Energy of activation
  • Reaction rate
  • Frequency factor

Answer :Rate constant

The role of a catalyst in a chemical reaction is to change the:


Options are :

  • Final products
  • Heat of reaction
  • Equilibrium constant
  • Activation energy

Answer :Activation energy

Which of the following fixes the volume of a batch reactor for a particular conversion and production rate ?


Options are :

  • Operating conditions (e.g. pressure and temperature)
  • Rate constant
  • Density of mixture
  • None of these

Answer :Density of mixture

For a first order chemical reaction, the rate constant:


Options are :

  • Has unit of time-1
  • Is not a function of the unit of time
  • Changes on changing the concentration units
  • None ofthese

Answer :Has unit of time-1

Chemical Reaction Engineering MCQ Practice Questions (Chem) Set 1

Limiting reactant in a chemical reaction decides the:


Options are :

  • Reaction speed
  • Equilibrium constant
  • Rate constant
  • Conversion

Answer :Conversion

In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants)


Options are :

  • A-N
  • A
  • N
  • A+N

Answer :A+N

The rate of an autocatalytic reaction,

, is given by -rA = k . CA . CB. In this case, the:


Options are :

  • Rate of disappearance of reactant A is maximum, where CA = CB
  • Plot of - rA Vs CA is a straight line with slope k
  • Plot of - rA Vs CA is a hyperbola
  • None of these

Answer :Rate of disappearance of reactant A is maximum, where CA = CB Plot of - rA Vs CA is a hyperbola

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


Options are :

  • Data in insufficient; can't be predicted
  • Remain same
  • Decrease
  • Increase

Answer :Increase

When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value


Options are :

  • Half
  • None of these
  • Equal
  • Twice

Answer :Half

The rate at which a chemical substance reacts is proportional to its:


Options are :

  • Atomic weight
  • Active mass
  • Molecular weight
  • Equivalent weight

Answer :Active mass

If ?G (free energy change) for a chemical reaction is very large and negative, then the reaction is:


Options are :

  • Very much feasible
  • Just feasible
  • Not feasible
  • Unpredictable as ?G is no measure of feasibility of a reaction

Answer :Very much feasible

For a heterogenous 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:


Options are :

  • Surface Kc/(1 + TS) reaction between absorbed A and B in the gas phase
  • Desorption of C
  • Surface reaction between A in the gas phase and absorbed B
  • Surface reaction between absorbed A and absorbed B

Answer :Desorption of C

When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ coloumn


Options are :

  • Bubble
  • Tray
  • Spray
  • Packed

Answer :Bubble

In the converter of the contact process for the manufacture of H2SO4 the equilibrium conversion of SO2 __________ (A) __________ with increase in temperature and __________ (B) __________ with increase in the mole ratio of SO2 to air


Options are :

  • (A) decreases (B) increases
  • (A) increases (B) decreases
  • (A) decreases (B) decreases
  • (A) increases (B) increases

Answer :(A) decreases (B) increases

The reactions of high molecularity are rare, because:


Options are :

  • of very large activation energy of many bodies
  • of low probability of many body collisions
  • of requirement of very large concentration for such reactions
  • many body collisions are not favoured energetically

Answer :of low probability of many body collisions

Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction


Options are :

  • Order
  • None of these
  • Molecularity
  • Overall order

Answer :Overall order

In an exothermic reaction, the energy of the reacting substances as compared to that of products is:


Options are :

  • Less
  • Same
  • More
  • Either A or B; depends on order of reaction

Answer :More

The reactions with low activation energy are:


Options are :

  • Non-spontaneous
  • Slow
  • Fast
  • Always spantaneous

Answer :Fast

BET apparatus is used to determine the:


Options are :

  • Porosity of the catalyst bed
  • Specific surface of a porous catalyst
  • Pore diameter
  • Pore size distribution

Answer :Specific surface of a porous catalyst

In the fluid catalytic cracker (FCC), the cracking reaction is __________ (A) and the regeneration is___(B) __________


Options are :

  • (A) exothermic (B) endothermic
  • (A) exothermic (B) exothermic
  • (A) endothermic (B) enodthermic
  • (A) endothermic (B) exothermic

Answer :(A) endothermic (B) exothermic

Kinetics of a solid catalysed reaction can best be studied in a __________ reactor


Options are :

  • None of these
  • Plug-flow
  • Batch
  • Mixed

Answer :Mixed

Comment / Suggestion Section
Point our Mistakes and Post Your Suggestions