Which of the following is the optimum operating condition for an
exothermic reversible reaction taking place in a plug-flow reactor?
(A) Temperature should be high in the beginning and decreased towards the
end of the reaction
(B) Very low temperature should be used throughout the reaction
(C) Very high temperature should be used throughout the reaction
(D) None of these

1 Answer

Answer :

(A) Temperature should be high in the beginning and decreased towards the
end of the reaction

Related questions

Description : 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 (C) Is at the highest allowable temperature throughout (D) First increases and then decreases

Last Answer : (C) Is at the highest allowable temperature throughout

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

Description : 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 exit of the reactor (C) Maximum at the centre of the reactor (D) Constant throughout the reactor

Last Answer : (A) Maximum at the inlet of the reactor

Description : 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

Last Answer : (B) Velocity of reaction can be controlled

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

Description : 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 ... D) Half life of a reaction increases with increased initial concentration for reaction orders more than one

Last Answer : (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same

Description : In case of staged packed bed reactors carrying out exothermic reaction, use (A) High recycle for pure gas (B) Plug flow for dilute liquid requiring no large preheating of feed (C) Cold shot operations for a ... preheating to bring the stream upto the reaction temperature (D) All (A), (B) and (C)

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

Description : For the reversible exothermic reaction, N2 + 3H2 ⇌ 2NH3, increase of pressure would (A) Shift the equilibrium towards right (B) Give higher yield of NH3 (C) Both (B) and (C) (D) Neither (A) nor (B)

Last Answer : (C) Both (B) and (C)

Description : Pick out the correct statement. (A) The available energy in an isolated system for all irreversible (real) processes decreases (B) The efficiency of a Carnot engine increases, if the sink temperature is decreased ... condition is the change in Helmholtz free energy (D) All (A), (B) and (C)

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

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

Description : A back mix reactor is (A) Suitable for gas phase reactions (B) Ideal at very low conversion (C) Same as plug flow reactor (PFR) (D) Same as ideal stirred tank reactor

Last Answer : (D) Same as ideal stirred tank reactor

Description : An exothermic reaction takes place in an adiabatic reactor. The product temperature __________ reactor feed temperature. (A) Is always equal to (B) Is always greater than (C) Is always less than (D) May be greater or less than

Last Answer : (B) Is always greater than

Description : Pick out the wrong statement. (A) The integral method of analysing kinetic data is used when the data is scattered (B) The differential method of analysing kinetic data requires more accurate ... less than one for identical feed composition, flow rate, conversion and for all positive reaction orders

Last Answer : (C) When the reaction rate is independent of temperature, the reaction is said to be of zero order

Description : The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3 is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit ... /kmole. K (may be assumed to be independent of temperature)) (A) 400 (B) 500 (C) 600 (D) 1000

Last Answer : (C) 600

Description : Pick out the wrong statement. (A) The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively (B) Space time in a flow reactor is a ... ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in longitudinal direction

Last Answer : (C) Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty

Description : Conversion increases with increase in temperature in case of a/an__________ reaction. (A) Autocatalytic (B) Irreversible (C) Reversible endothermic (D) Reversible exothermic

Last Answer : (C) Reversible endothermic

Description : Photochemical reaction rate does not depend significantly on temperature, because (A) It is a reversible reaction (B) It is an exothermic reaction (C) The energy of reacting molecules exceeds the activation energy by absorption of light (D) None of these

Last Answer : (C) The energy of reacting molecules exceeds the activation energy by absorption of light

Description : In case of a/an __________ chemical reaction, conversion increases with the rise in temperature. (A) Reversible exothermic (B) Irreversible exothermic (C) Irreversible endothermic (D) Reversible endothermic

Last Answer : (D) Reversible endothermic

Description : Fractional conversion __________ for an exothermic reversible chemical reaction, when the temperature is maximum. (A) Increases (B) Remains unchanged (C) Decreases (D) Unpredictable from the data

Last Answer : (C) Decreases

Description : A typical example of an exothermic reversible reaction conducted at high pressure in industry is (A) Dehydration of ethanol (B) Methanol synthesis (C) Reformation of methane (D) Polymerisation of ethylene

Last Answer : (A) Dehydration of ethanol

Description : Recitation in learning appears most profitable when introduced Options: A) At the beginning of the learning period B) Uniformity throughout the learning period C) Towards the end of the learning period D) Only as preparation for the testing period

Last Answer : C) Towards the end of the learning period 

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

Last Answer : (C) 1.60

Description : A backmix reactor (A) Is same as plug-flow reactor (B) Is same as ideal stirred tank reactor (C) Employs mixing in axial direction only (D) Is most suitable for gas phase reaction

Last Answer : (B) Is same as ideal stirred tank reactor

Description : 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) Goes through a maximum ... through a minimum along the length of the reactor (D) Is maximum at the exit of the reactor

Last Answer : (A) Is maximum at the inlet of the reactor

Description : With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion). (A) Increases (B) Decreases (C) Remain same (D) Increases linearly

Last Answer : (A) Increases

Description : Kinetics of a catalytic reaction can be best studied on a/an __________ reactor. (A) Mixed (B) Integral (plug flow) (C) Differential (flow) (D) Either (A), (B) and (C)

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

Description : The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is __________ that of mixed reactor. (A) Greater than (B) Equal to (C) Smaller than (D) Unpredictable from the data

Last Answer : (C) Smaller than

Description : For series reaction, the relative yield (A) Is always greater for plug-flow reactor than for the single CSTR of the same volume (B) Statement in (A) is wrong (C) Decreases with increasing conversion (D) Both (A) and (C) hold good

Last Answer : (D) Both (A) and (C) hold good

Description : Kinetics of a solid catalysed reaction can best be studied in a __________ reactor. (A) Batch (B) Plug-flow (C) Mixed (D) None of these

Last Answer : (C) Mixed

Description : 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) For an ideal ... D) Reaction rate does not decrease appreciably as the reaction proceeds in case of an autocatalytic reaction

Last Answer : (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity

Description : The gas phase reaction 2A ⇌ B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is (A) 2/3 (B) 5/8 (C) 1/3 (D) 3/8

Last Answer : (B) 5/8

Description : For all positive reaction orders for a particular duty, (A) Mixed reactor is always larger than the plug-flow reactor (B) Ratio of the volume of the mixed reactor to that of the plug-flow ... (C) Reactor size is independent of the type of flow (D) Density variation during reaction affects design

Last Answer : (A) Mixed reactor is always larger than the plug-flow reactor

Description : Formation of ammonium carbamate by reaction of NH3 with CO2 is a/an __________ reaction. (A) Catalytic (B) Exothermic (C) Endothermic (D) Reversible

Last Answer : (B) Exothermic

Description : Dehydration of ammonium carbamate (to produce urea) is a/an __________ reaction. (A) Reversible (B) Catalytic (C) Exothermic (D) Endothermic

Last Answer : (D) Endothermic

Description : In the reversible reaction of the type, A + B ⇌ AB, in general (A) Both forward and backward reactions will be exothermic (B) Neither of the reactions will be endothermic (C) ... will be endothermic (D) The combination reaction will be endothermic, while the dissociation reaction will be exothermic

Last Answer : (C) The combination reaction will be exothermic, while the dissociation reaction will be endothermic

Description : When an exothermic reversible reaction is conducted adiabatically, the rate of reaction (A) Continuously increases (B) Continuously decreases (C) Passes through a maximum (D) Passes through a minimum

Last Answer : (C) Passes through a maximum

Description : For high conversion in a highly exothermic solid catalysed reaction, use a __________ bed reactor. (A) Fixed (B) Fluidised bed reactor followed by a fixed (C) Fixed bed reactor followed by a fluidised (D) Fluidised

Last Answer : (B) Fluidised bed reactor followed by a fixed

Description : Semibatch reactor is preferred, when a/an (A) A highly exothermic reaction is to be controlled (B) Undesirable side reaction (at high concentration of one of the reactants) is to be avoided (C) A gas is to be reacted with liquid (e.g. hydrogenation of fat) (D) All (A), (B), and (C

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

Description : Cracking is (A) An exothermic reaction (B) An endothermic reaction (C) Favoured at very low temperature (D) None of these

Last Answer : (B) An endothermic reaction

Description : Hydrogenation of oil takes place in a/an __________ reactor. (A) Autothermal (B) Trickle bed (C) Plug flow (D) None of these

Last Answer : (B) Trickle bed

Description : Pick out the wrong statement. (A) In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time (B) In a semi-batch reactor, ... system (D) In a continuous flow reactor, both the reactants and the products flow out continuously

Last Answer : (C) In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system

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

Description : 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 ... no change in number of moles in gaseous reaction (D) All (A), (B) and (C)

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

Description : Though kinetics of ammonia synthesis dictates the use of low temperature for high equilibrium conversion, yet it is kept moderately high (550°C), because at low temperature (A) Rate of reaction is very low ... (C) Space velocity of gas is very low resulting in decreased conversion (D) None of these

Last Answer : (A) Rate of reaction is very low

Description : Spacing of stirrups in a rectangular beam, is (A) Kept constant throughout the length (B) Decreased towards the centre of the beam (C) Increased at the ends (D) Increased at the centre of the beam

Last Answer : Answer: Option D

Description : To ensure uniform pressure distribution, the thickness of the foundation, is A) Kept uniform throughout (B) Increased gradually towards the edge (C) Decreased gradually towards the edge (D) Kept zero at the edge

Last Answer : Answer: Option C

Description : Forward reaction will be favoured for the exothermic reaction, represented by CO + H2O ⇌ CO2 + H2, by (A) Low temperature and high pressure (B) Low temperature and low pressure (C) High temperature and high pressure (D) High temperature and low pressure

Last Answer : (A) Low temperature and high pressure

Description : The weather condition is optimum for herbicidal weed control? a). High temperature low humidity b). High temperature high humidity c). warm temperature high humidity d). cold temperature low humidity

Last Answer : c). warm temperature high humidity

Description : Space velocity (A) Describes the extensive operating characteristics of a tubular flow reactor (B) Is the maximum feed rate per unit volume of reactor for a given conversion (C) Is a measure of the ease of the reaction (D) All (A), (B) and (C)

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