Download PDF
Free download in PDF Chemical Reaction Engineering Short Questions & Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
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
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%
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
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
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
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.
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.
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.
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
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
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.
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
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.
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.
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.
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
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.
58
A certain first-order reaction is half completed in 23 minutes. The rate constant for the reaction must be
[A]
0.030 s-1
[B]
0.030 min-1
[C]
0.030 hr-1
[D]
0.10 min-1
59
The half-line period of a first-order reaction (t1/2) and the rate constant (k) are related by
[A]
t1/2 = k
[B]
t1/2 = 2.303/k
[C]
t1/2 = 0.693/k
[D]
t1/2 = 7.67/k
60
In the question 109 the holding time is
[A]
sec
[B]
3 sec
[C]
1 sec
[D]
2 sec.
Please share this page