Chemical Reaction Engineering Short Questions & Answers | Chemical Reaction Engineering Quiz

41 One litre per second of gaseous reactant A is introduced into a mixed reactor. The stoichiometry is A ? 3R, the conversion is 50% and under these conditions the leaving flow rate is 2 litres per second. The space-time for this operation is

A 1 sec

B sec

C 2 sec

D ? sec

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Answer: ? sec

42 Pure gaseous reactant A (CAO = 100 millimol/litre) is fed at steady rate into a mixed reactor where it dimerizes (2A ? R). For a certain gas feed rate the concentration of A in the exit stream is found to be 50 millimol/litre. The fractional conversion of A is

A 50%

B 33.33%

C 40%

D 66.67%

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Answer: 33.33%

43 N plug flow reactors in series with a total volume V gives the same conversion as a single plug flow reactor of volume V. The above statement is true for

A zero-order reactions only

B first-order reactions only

C second-order reactions only

D all reaction orders

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Answer: zero-order reactions only

44 For identical feed compostion and flow rate, N plug flow reactors in series with a total volume V gives the same conversion as a single

A plug flow reactor of volume V

B CSTR of volume V

C Plug flow reactor of volume V/N

D plug flow reactor of volume NV

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Answer: plug flow reactor of volume NV

45 The batch reactor has the disadvantage(s) of

A high labour and handling cost

B Poorer quality control of the product

C considerable shutdown time to empty, clean out and refill

D all of the above

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Answer: considerable shutdown time to empty, clean out and refill

46 For identical feed composition, flow rate, conversion and for all positive reaction orders, the ratio of volumes of the mixed reactor to the plug flow reactor is

A always one

B always less than one

C always greater than one

D equal to the order of reaction.

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Answer: always one

47 For constant-density systems, the performance equations are identical for

A batch reactor and plug flow reactor

B batch reactor and backmix reactor

C plug flow reactor and backmix reactor

D batch reactor, plug flow reactor and beckmix reactor.

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Answer: batch reactor and backmix reactor

48 The space-velocity of 2 hr-1 means

A that every two hours one reactor volume of feed at specified conditions is being treated by the reactor

B that two reactor volumes of feed at specified conditions are bing fed into the reactor per hour

C that the actual reactor volume is double that of the optimum reactor volume

D that one-half reactor volume of feed at specified conditions are being fed into the reactor.

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Answer: that two reactor volumes of feed at specified conditions are bing fed into the reactor per hour

49 The space-velocity is the proper performance measure of flow reactors. The space-velocity has the units of

A time

B (tme)-1

C velocity

D (velocity)-1

View Answer

Answer: time

50 For the isothermal gas-phase reaction A ? 3B, the fractional change in volume of the system between no conversion and complete conversion is

A 1

B 3

C 2

D 2?3

View Answer

Answer: 2

51 For the irreversible unimolecular-type first-order reaction

A the fractional conversion at any time is same for constant volume systems and variable-volume systems

B the fraction conversion at any time is more for constant volume systems than variable-volume systems

C the fractional conversion at any time is less for constant-volume systems than variable-volume systems

D the concentration of reactant at any time is same for constant-volume systems and variable-volume systems.

View Answer

Answer: the fractional conversion at any time is same for constant volume systems and variable-volume systems

52 The irreversible reaction is simply the special case of the reversible reaction if

A The concentration of the reactant at equilibrium conditions is zero

B the fractional conversion of the reactant at equilibrium conditions is zero

C the equilibrium constant is zero

D the equilibrium constant is one

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Answer: The concentration of the reactant at equilibrium conditions is zero

53 A reaction in which one of the products of reaction acts as a catalyst is called

A a catalytic reaction

B a photochemical reaction

C an autocatalytic reaction

D a biochemical reaction.

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Answer: an autocatalytic reaction

54 A reaction is of zero order when the rate of reaction is

A proportional to the concentration of reactant

B inversely proportional to the concentration of reactant

C independent of the concentration of reactant

D independent of temperature.

View Answer

Answer: independent of the concentration of reactant

55 The integral method of analyzing kinetic data

A is easy to use and is recommended when testing specific mechanisms, or relatively simple rate expression

B is used when the ata are scattered

C assumes a particular form of rate equation

D all of these answers.

View Answer

Answer: all of these answers.

56 A certain reaction has arate expression -rA = 0.001 CA2, mol/cm3 min. If the concentration is to be expressed in mol/lit. and time in hours. The value of the rate constant would be

A 0.60 hr-1 (mol/l)-1

B 0.001 hr-1 (mol/l)-1

C 60.000 hr-1 (mol/l)-1

D 0.06 hr-1 (mol/l)-1

View Answer

Answer: 0.60 hr-1 (mol/l)-1

57 The rate constant for N2O5 decomposition reaction is found to be 6.2 x 10-4 S-1. The time required for one-half the N2O5 in a sample to be decomposed is

A 6.2 x 104 s

B 3710 s

C 1513 s

D 1120 s.

View Answer