Space time equals the mean residence time (A) When the density of the reaction mixture is constant (B) For large diameter tubular reactor (C) For narrow diameter tubular reactor (D) For CSTR

Space time equals the mean residence time
(A) When the density of the reaction mixture is constant
(B) For large diameter tubular reactor
(C) For narrow diameter tubular reactor
(D) For CSTR
by

1 Answer

Answer :

(A) When the density of the reaction mixture is constant
by

Related questions

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The use of space time is preferred over the mean residence time in the design of a/an (A) Batch reactor (B) Ideal tubular-flow reactor (C) Slurry reactor (D) CSTR

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Mean residence time is equal to the space time, when (A) The feed rate is measured at temperature and pressure in the reactor (B) The temperature, pressure and the density of reaction mixture remains constant throughout the reactor (C) There is no change in number of moles in gaseous reaction (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

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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

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Last Answer : (C) 1

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A reactor is generally termed as an autoclave, when it is a (A) High pressure batch reactor (B) Atmospheric pressure tank reactor (C) High pressure tubular reactor (D) Atmospheric pressure CSTR(

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For the same residence time, which one will give the maximum conversion? (A) Single stirred tank (v = 5 litres) (B) Two stirred tank (each of 2.5 litres) in series (C) Stirred tank followed by tubular flow reactor (each of 2.5 litres) (D) Single tubular flow reactor (v = 5 litres)

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Last Answer : (D) Single tubular flow reactor (v = 5 litres)

A first order reaction requires two unequal sized CSTR. Which of thefollowing gives higher yield?(A) Large reactor followed by smaller one(B) Smaller reactor followed by larger one(C) Either of the arrangement (A) or (B) will give the same yield(D) Data insufficient, can't be predicted

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In a semi-batch reactor, (A) Mixing takes place in axial direction only (B) Velocity of reaction can be controlled (C) Condition similar to plug flow reactor exists (D) Residence time is constant

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A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is (A) d(VCA )/dt = -F (CAF - CA ) - kCA 2V (B) d(VCA )/dt = F (CAF - CA ) - kCA 2V (C) d(VCA )/dt = -FCA - kCA 2V (D) d(VCA )/dt = FCAF - kCA 2V

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The exit age distribution curve E(t) for an ideal CSTR with the average residence time, τ, is given by (A) e -t/τ (B) e -t/τ /τ (C) 1 - e -t/τ (D) 1 - (e -t/τ /τ)

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With the same reaction time, initial concentration and feed rate, the reaction 2A → B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be (A) Higher in P.F. reactor (B) Higher in CSTR (C) Same in both the reactors (D) Data insufficient; can't be predicted

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Last Answer : (C) No change

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The space time is equivalent to the holding time in a steady state mixed reactor for (A) Non-isothermal gas reaction (B) Variable fluid density systems (C) Constant fluid density systems(D) Gas reactions with changing number of moles

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For a tubular flow reactor with uniform concentration and temperature, the independent variable is (A) Time (B) Length (C) Diameter (D) None of these

Description : For a tubular flow reactor with uniform concentration and temperature, the independent variable is (A) Time (B) Length (C) Diameter (D) None of these

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Pick out the wrong statement. (A) 'Hold back' is defined as the fraction of material that stays longer than the mean residence time (B) Study of non-ideal flow reactor is done experimentally by stimulus￾response technique (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

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Space time in flow reactor is (A) Usually equal to the residence time (B) The reciprocal of the space velocity(C) A measure of its capacity(D) Both (A) and (B)

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Which of the following fixes the volume of a batch reactor for a particular conversion and production rate? (A) Operating conditions (e.g. pressure and temperature) (B) Rate constant (C) Density of mixture (D) None of these

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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) 0.80 (B) 1.33 (C) 1.60 (D) 2.67

Description : 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 ... (in hours) for 40% conversion of P is (A) 0.80 (B) 1.33 (C) 1.60 (D) 2.67

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Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (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

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The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line? (A) XA Vs . τ (B) XA Vs ln τ (C) XA /(1 - XA )Vs τ (D) XA (1 - XA )Vs τ

Description : The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line? (A) XA Vs . τ (B) XA Vs ln τ (C) XA /(1 - XA )Vs τ (D) XA (1 - XA )Vs τ

Last Answer : (A) XA Vs . τ

A stirred tank reactor compared to tubular-flow reactor provides (A) More uniform operating conditions (B) Permits operation at the optimum temperature for a long reaction time (C) Higher overall selectivity for a first order consecutive reaction (D) All (A), (B) and (C

Description : A stirred tank reactor compared to tubular-flow reactor provides (A) More uniform operating conditions (B) Permits operation at the optimum temperature for a long reaction time (C) Higher overall selectivity for a first order consecutive reaction (D) All (A), (B) and (C

Last Answer : (D) All (A), (B) and (C

Exothermic reactions are best carried out in (A) A CSTR (B) CSTR in series (C) A plug flow reactor followed by CSTR (D) CSTR followed by a plug flow reactor

Description : Exothermic reactions are best carried out in (A) A CSTR (B) CSTR in series (C) A plug flow reactor followed by CSTR (D) CSTR followed by a plug flow reactor

Last Answer : (D) CSTR followed by a plug flow reactor

Backmixing is most predominant in (A) A well stirred batch reactor (B) A plug-flow reactor (C) A single CSTR (D) CSTR's connected in series

Description : Backmixing is most predominant in (A) A well stirred batch reactor (B) A plug-flow reactor (C) A single CSTR (D) CSTR's connected in series

Last Answer : (C) A single CSTR

The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is (A) Backmix reactor (B) Plug flow reactor (C) Series of CSTR (D) PFR in series

Description : The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is (A) Backmix reactor (B) Plug flow reactor (C) Series of CSTR (D) PFR in series

Last Answer : A) Backmix reactor

For an autocatalytic reactor, the suitable reactor set up is(A) P.F. reactors in series (B) CSTR in series (C) CSTR followed by P.F. reactor (D) P.F. reactor followed by CSTR

Description : For an autocatalytic reactor, the suitable reactor set up is (A) P.F. reactors in series (B) CSTR in series (C) CSTR followed by P.F. reactor (D) P.F. reactor followed by CSTR

Last Answer : (C) CSTR followed by P.F. reactor

For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by (A) A Dirac delta function (B) A step function (C) A ramp function (D) None of the above

Description : For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by (A) A Dirac delta function (B) A step function (C) A ramp function (D) None of the above

Last Answer : (D) None of the above

Autocatalytic reactions are best carried out in a (A) CSTR (B) CSTR in series (C) Plug flow reactor (D) Recycle reactor

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Last Answer : (D) Recycle reactor

The preferred reacting system for oxidation of o-xylene to phthalic anhydride is (A) Jacketed liquid phase CSTR (B) Jacketed steam heated multitubular reactor (C) Multitubular reactor with cooling (D) Multistage multitubular reactor with interstage cooling

Description : The preferred reacting system for oxidation of o-xylene to phthalic anhydride is (A) Jacketed liquid phase CSTR (B) Jacketed steam heated multitubular reactor (C) Multitubular reactor with cooling (D) Multistage multitubular reactor with interstage cooling

Last Answer : (A) Jacketed liquid phase CSTR

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) 0.15(B) 0.30 (C) 0.60 (D) 0.90

Description : 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 ... conditions are the same for CSTR and PFR. (A) 0.15 (B) 0.30 (C) 0.60 (D) 0.90

Last Answer : (C) 0.60

Which of the following is the most suitable for very high pressure gas phase reaction? (A) Batch reactor (B) Tubular flow reactor (C) Stirred tank reactor (D) Fluidised bed reactor

Description : Which of the following is the most suitable for very high pressure gas phase reaction? (A) Batch reactor (B) Tubular flow reactor (C) Stirred tank reactor (D) Fluidised bed reactor

Last Answer : (B) Tubular flow reactor

In an ideal mixed reactor (at steady state), the (A) Space time is equivalent to holding time for constant density systems (B) Composition throughout the reactor remains same (C) Exit stream has the same composition as the fluid within the reactor (D) All (A), (B) and (C)

Description : In an ideal mixed reactor (at steady state), the (A) Space time is equivalent to holding time for constant density systems (B) Composition throughout the reactor remains same (C) Exit stream has the same composition as the fluid within the reactor (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

A plug-flow reactor is characterised by (A) High capacity (B) Presence of axial mixing (C) Presence of lateral mixing (D) Constant composition and temperature of reaction mixture

Description : A plug-flow reactor is characterised by (A) High capacity (B) Presence of axial mixing (C) Presence of lateral mixing (D) Constant composition and temperature of reaction mixture

Last Answer : (C) Presence of lateral mixing

For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of: (A) Ideal plug flow (B) Bypass (C) Dead zone (D) Channelling

Description : For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of: (A) Ideal plug flow (B) Bypass (C) Dead zone (D) Channelling

Last Answer : (C) Dead zone

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 space time of a reaction (C) Half of the residence time of a reaction (D) None of these

Description : 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 space time of a reaction (C) Half of the residence time of a reaction (D) None of these

Last Answer : (A) The time required to reduce the concentration of the reacting substance to half its initial value

In an ideal tubular-flow reactor (A) There is no mixing in longitudinal direction (B) Mixing takes place in radial direction (C) There is a uniform velocity across the radius (D) All (A), (B) and (C)

Description : In an ideal tubular-flow reactor (A) There is no mixing in longitudinal direction (B) Mixing takes place in radial direction (C) There is a uniform velocity across the radius (D) All (A), (B) and (C)

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The energy balance equation over a tubular reactor under transient conditions is (A) An ordinary non-linear differential equation (B) An algebraic differential equation (C) A linear partial differential equation(D) A non-linear partial differential equation

Description : The energy balance equation over a tubular reactor under transient conditions is (A) An ordinary non-linear differential equation (B) An algebraic differential equation (C) A linear partial differential equation (D) A non-linear partial differential equation

Last Answer : (C) A linear partial differential equation

. In case of a __________ reactor, the composition in the reactor and at the exit of the reactor is the same. (A) Semi-batch(B) Tubular(C) Batch(D) Back-mix

Description : . In case of a __________ reactor, the composition in the reactor and at the exit of the reactor is the same. (A) Semi-batch (B) Tubular (C) Batch (D) Back-mix

Last Answer : (D) Back-mix

In a CSTR __________ varies with time. (A) Reaction rate (B) Concentration (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : In a CSTR __________ varies with time. (A) Reaction rate (B) Concentration (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (D) Neither (A) nor (B)

A first order reaction requires two equal sized CSTR. The conversion is (A) Less when they are connected in series (B) More when they are connected in series (C) More when they are connected in parallel (D) Same whether they are connected in series or in parallel

Description : A first order reaction requires two equal sized CSTR. The conversion is (A) Less when they are connected in series (B) More when they are connected in series (C) More when they are connected in parallel (D) Same whether they are connected in series or in parallel

Last Answer : (B) More when they are connected in series