Q.1

In an ideal tubular-flow reactor

  • there is no mixing in longitudinal direction.
  • mixing takes place in radial direction.
  • there is a uniform velocity across the radius.
  • all (a), (b) and (c).
Q.2

Radioactive decay follows __________ order kinetics.

  • first
  • second
  • third
  • zero.
Q.3

Rate of an autocatalytic chemical reaction is a function of

  • temperature only.
  • pressure only.
  • composition only.
  • all (a), (b) and (c).
Q.4

In flow reactors, the performance equations interrelate the rate of reaction to the

  • feed rate.
  • reactor volume,
  • extent of reaction.
  • all (a), (b) and (c).
Q.5

The value of steric factor 'P' in the equation k = PZeE/RT usually ranges from

  • l.0 to 10-8
  • l.l.to 102
  • 0.1 to 0.9
  • none of these
Q.6

A first order reaction requires two unequal sized CSTR. Which of the following gives higher yield ?

  • Large reactor followed by smaller one.
  • Smaller reactor followed by larger one.
  • Either of the arrangement (a) or (b) will give the same yield.
  • Data insufficient, can't be predicted.
Q.7

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

  • 0.33
  • 0.5
  • 1
  • data insufficient, can't be predicted
Q.8

Which of the following will favour the reverse reaction in a chemical equilibrium reaction ?

  • Increasing the concentration of one of the reactants.
  • Increasing the concentration of one or more of the products.
  • Removal of at least one of the products at regular interval.
  • None of these.
Q.9

The units of frequency factor in Arhenious equation

  • are the same as those of the rate constant.
  • depend on the order of the reaction.
  • depend on temperature, pressure etc. of the reaction.
  • are cycles per unit time.
Q.10

In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation.

  • adiabatic
  • isothermal
  • non-adiabatic
  • none of these.
Q.11

For a tubular reactor with space time 'τ' and residence time 'θ', the following statement holds good.

  • τ and θ are always equal.
  • τ = θ , when the fluid density changes in the reactor.
  • τ = θ , for an isothermic tubular reactor in which the density of the process fluid is constant.
  • τ = θ , for a non-isothermal reactor.
Q.12

Signal normally used to study non-ideal flow by stimulus response technique is __________ input.

  • pulse
  • step
  • both (a) & (b)
  • neither (a) nor (b).
Q.13

For a heterogeneous catalytic reaction

  • free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction.
  • a relatively small amount of catalyst can cause the conversion of large amount of reactants which does not mean that catalyst concentration is important.
  • the catalyst does not form an intermediate complex with the reactant.
  • the surface of the catalyst does not play an important role during reaction.
Q.14

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 isif Arrhenious law is used. What will be this ratio, if transition state theory is used with the same value of E/R?

  • 1.6
  • 2
  • 2.24
  • 2.5
Q.15

For a tubular reactor with space time 'τ' and residence time 'θ', the following statement holds good.

  • τ and θ are always equal.
  • τ = θ , when the fluid density changes in the reactor.
  • τ = θ , for an isothermic tubular reactor in which the density of the process fluid is constant.
  • τ = θ , for a non-isothermal reactor.
Q.16

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

  • activation
  • potential
  • binding
  • threshold
Q.17

A catalyst

  • initiates a reaction.
  • lowers the activation energy of reacting molecules.
  • is capable of reacting with any one of the reactants.
  • can not be recovered chemically unchanged at the end of a chemical reaction.
Q.18

Which of the following curves shows the effect of temperature on the extent of gas-solid adsorption at a given pressure ?

  • Langmuir adsorption isotherm
  • Adsorption isobar
  • Freundlich adsorption isotherm
  • None of these
Q.19

Arrhenious equation represents graphically the variation between the __________ and temperature.

  • rate of reaction
  • frequency factor
  • rate constant
  • activation energy
Q.20

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.

  • both conversion as well as concentration are same
  • conversion in both will be the same but concentrations will be different
  • both the conversion as well as concentrations will be different
  • none of these.
Q.21

For a zero order reaction, the concentration of product increases with the

  • increase of reaction time.
  • increase in initial concentration.
  • total pressure.
  • decrease in total pressure.
Q.22

B.E.T. method can be used to determine the __________ of a porous catalyst.

  • solid density
  • pore volume
  • surface area
  • all (a), (b) and (c)
Q.23

A catalyst

  • initiates a reaction.
  • lowers the activation energy of reacting molecules.
  • is capable of reacting with any one of the reactants.
  • can not be recovered chemically unchanged at the end of a chemical reaction.
Q.24

For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to l/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times.

  • 8
  • 16
  • 1/8
  • 1/16
Q.25

Pick out the correct statement.

  • A lower temperature favours the reaction of lower activation energy.
  • The dispersion number for a reactor/vessel is uL/D.
  • The rate controlling step in a reaction involving many steps is the fastetst step.
  • Pore volume and porosity of a catalyst is measured by Brunaver-Emmet-Teller (BET) technique.
Q.26

For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to l/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times.

  • 8
  • 16
  • 1/8
  • 1/16
Q.27

Conversion increases with increase in temperature in case of a an __________ reaction.

  • autocatalytic
  • irreversible
  • reversible endothermic
  • reversible exothermic
Q.28

Which of the following is not a chemical step in a fluid solid catalytic reaction ?

  • Surface chemical reaction
  • Adsorption
  • Desorption
  • None of these
Q.29

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

  • activation
  • potential
  • binding
  • threshold
Q.30

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

  • ∝ CA.
  • ∝ 1/CA.
  • independent of temperature.
  • none of these.
Q.31

'Unreacted core model' represents the reaction involving

  • combustion of coal particles.
  • roasting of sulphide ores.
  • manufacture of carbon disulphide from elements.
  • none of these.
Q.32

Differential method for analysing the kinetic data is used

  • for testing complicated mechanisms.
  • when the data are scattered.
  • when rate expressions are very simple.
  • none of these.
Q.33

When all the limiting reactant is consumed in the reaction, the operational yield __________ the relative yield.

  • is greater than
  • is smaller than
  • equals
  • can be either greater or smaller than (depends on the type of reaction)
Q.34

__________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction.

  • Gas film diffusion
  • Ash diffusion
  • Chemical reaction
  • none of these
Q.35

For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by

  • a dirac delta function
  • a step function.
  • a ramp function.
  • none of the above
Q.36

__________ catalytic reaction is involved in the thermal cracking of gas oil.

  • Homogeneous
  • Homogeneous non
  • Heterogeneous
  • Heterogeneous non
Q.37

Variables affecting the rate of homogeneous reactions are

  • pressure and temperature only.
  • temperature and composition only.
  • pressure and composition only.
  • pressure, temperature and composition.
Q.38

Pick out the wrong statement.

  • 'Hold back' is defined as the fraction of material that stays longer than the mean residence time.
  • Study of non-ideal flow reactor is done experimentally by stimulus-response technique.
  • For studying a chemical reaction, it is desirable to monitor the reactants during initial stages and the products during the final stages of reaction.
  • A batch reactor can not be used to study the kinetics of catalytic reaction.
Q.39

In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will

  • remain the same
  • be halved
  • also be. doubled
  • become one fourth
Q.40

The half life period of a first order reaction is

  • always the same irrespective of the reaction.
  • independent on initial concentration of the reactants.
  • proportional to the initial concentration of reactants.
  • half the specific rate constant.
Q.41

'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

  • pressure
  • temperature
  • both (a) & (b)
  • neither (a) nor (b)
Q.42

An autothermal reactor is

  • most suitable for a second order reaction.
  • most suitable for a reversible reaction.
  • completely self-supporting in its thermal energy requirements.
  • isothermal in nature.
Q.43

'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

  • pressure
  • temperature
  • both (a) & (b)
  • neither (a) nor (b)
Q.44

Fluid flow in a real packed bed can be approximated as __________ model.

  • plug flow
  • dispersion
  • mixed flow
  • tank in series
Q.45

A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction.

  • less than
  • equal to
  • more than
  • equal to or more than
Q.46

Effectiveness factor of a catalyst pellet is a measure of the __________ resistance.

  • pore diffusion
  • gas film
  • chemical reaction
  • none of these
Q.47

A catalyst inhibitor

  • lessens its selectivity.
  • may be useful for suppressing undesirable side reactions.
  • is added in small quantity during the catalyst manufacture itself.
  • all(a), (b) and (c).
Q.48

For series reaction, the relative yield

  • decreases with increasing conversion.
  • is always greater for plug-flow reactor than for the single CSTR of the same volume.
  • statement in (a) is wrong.
  • both (a) and (c) hold good.
Q.49

For a series of reactions having k1 << k2, the reaction system can be approximated as

Q.50

The rate expression for a heterogenous catalytic reaction is given by, - rA = K.KA PA(1 + KA.PA + KR.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A)

  • E
  • E + ΔHA
  • E + ΔHA - ΔHR)
  • ΔHA + ΔHR
0 h : 0 m : 1 s