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Free download in PDF Chemical Reaction Engineering Objective Type 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.
(21)
Select the correct statement
[A]
Reactions with high activation energies are very temperature sensitive
[B]
Reactions with high activation energies are relatively temperature insensitive
[C]
Reactions with low activation energies are very temperature sensitive
[D]
A given reaction is much more temperature insensitive at low temperature than at high temperature.
Answer: Reactions with high activation energies are very temperature sensitive
(22)
From Arrhenius law a plot of In K versus 1/T give a straight line with a slope of (-E/R). The units of E/R are
[A]
K
[B]
cal
[C]
cal/K
[D]
K/cal.
(23)
What experimental information is necessary to determine the energy of activation for a chemical reaction? (k0 is an unknown constant in the Arrhenius equation)
[A]
The reaction rate constant at one temperature is sufficient
[B]
The reaction rate constants at two or more different temperatures must be known
[C]
The reaction rate constants at three different temperatures must be known
[D]
The reaction rate constants at two different temperatures and k0 must be known.
Answer: The reaction rate constants at two or more different temperatures must be known
(24)
Suppose doubling the concentration of a reactant increases the rate of reaction by a facator of 4, and tripling the concentration of the reactant increases the reaction rate by a factor of 9. Then the rate of reaction is proportional to the concentration of the reactant raised to the
[A]
first power
[B]
second power
[C]
third power
[D]
fourth power
(25)
The dimensions of the rate constant for nth order homogeneous reaction are
[A]
(time)-n
[B]
(time)-1 (concentration)1-n
[C]
(time)-n (concentration)n-1
[D]
(time) (concentration)n-1
Answer: (time)-1 (concentration)1-n
(26)
A reaction follows the rate expression rate = k CA If the rate is expressed in terms of mole/(1 sec) and the concentration of A (CA) is in mole/lit, the units of the first-order rate constant (k) are
[A]
1/(mol. Sec)
[B]
1/sec
[C]
mol/(1 sec)
[D]
sec.
(27)
For the chemical reaction A ? B, it is found that the rate of the reaction triples when concentration of A is increased 9 times. If rate ? CAn, what must n be for this reaction?
[A]
3
[B]
9
[C]
1?3
[D]
1?2
(28)
For the chemical reaction A ? B, it is found that the rate of the reaction increases by a factor of 8 when the concentration of A is doubled. If rate ? CAn, what must n be for this reaction?
[A]
2
[B]
1?3
[C]
3
[D]
4
(29)
For the chemical rection A ? B, it is found that the rate of the reaction quadruples when the concentration of A is doubled. If rate ? CAn, what must n be?
[A]
1?4
[B]
1
[C]
2
[D]
4
(30)
For the chemical rection A ? B, it is found that the rate of the reaction doubles as the concentration of A is doubled. If rate ? CAn, what must n be for this reaction?
[A]
0
[B]
1
[C]
2
[D]
0.5
31
For the chemical reaction 3A + B ? C, the rate of formation of C is 0.30 mole/(1 hr). The rate of disappearance of A is
[A]
0.30 mole / (1 hr)
[B]
0.90 mole / (I hr)
[C]
0.10 mole / (I hr)
[D]
?0.30 mole / (I hr)
Answer: 0.90 mole / (I hr)
32
Liquid A decomposes by irreversible first-order kinetics and the half-life period of this reaction is 12 min. The time required for 75% conversion of A is
[A]
21 min
[B]
16 min
[C]
24 min
[D]
18 min
33
Which of the following statements in incorrect?
[A]
A rise in temperature usually tends to reduce the reaction rate
[B]
A rise in temperature usually increases reaction rates
[C]
A rise in temperature does not affect photo-chemical reaction rates
[D]
A rise in temperature has no effect on catalysed reaction.
Answer: A rise in temperature usually tends to reduce the reaction rate
34
The rate constant of a reaction depends on
[A]
the temperature of the system
[B]
the time of reaction
[C]
the extent of reaction
[D]
the initial concentration of the reactants
Answer: the temperature of the system
35
The rate of reaction of any component is a function of
[A]
temperature of the system only
[B]
pressure of the system only
[C]
composition of the component only
[D]
temperature pressure and composition
Answer: temperature pressure and composition
36
At equilibrium
[A]
the rate of forward reaction is equal to the rate of backward reaction
[B]
the rate of forward reaction is more than the rate of backward reaction
[C]
the rate of forward reaction is less than the rate of backward reaction
[D]
chemical reaction stops
Answer: the rate of forward reaction is equal to the rate of backward reaction
37
Equilibrium state is
[A]
dynamic
[B]
static
[C]
neither dynamic nor static
[D]
sometimes static and sometimes dynamic
38
The rate at which a chemical substance reacts is proportional to its
[A]
equivalent weight
[B]
atomic weight
[C]
molecular weight
[D]
active mass
39
The rate constant for a first-order reaction
[A]
depends on the unit of time
[B]
has units of reciprocal time
[C]
does not change on changing the concentration units
[D]
all of the above
40
If the time required to change the concentration of reactant to half its original value is independent of the initial concentration the order of reaction is
[A]
zero
[B]
one
[C]
two
[D]
three
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