Order of Reaction
MCQs for CSIR NET & GATE
Chemical Kinetics
Topic wise Assignment-2
Q1. If the unit of the rate constant is L3
mol-3 s-1, the order of the reaction is
[NET June 2018]
(a) 1
(b) 2
(c) 3
(d) 4
Q2. Reaction between A and B is carried
out for different initial concentrations and the corresponding half life times
are measured. The data is listed in the table
[NET Dec 2017]
The
rate can be represented as
(a) k [A] [B]
(b) k [A]2
(c) k [A]2 [B]
(d) k [A] [B]2
Q3. The rate constant of a reaction is
1.25 x 10-4 mol L-1 s-1. If the initial
concentrations of the reactant is 0.250 mol L-1, the total time (in
seconds) required for complete conversion is _______.
[GATE 2017]
Q4. In kinetic study of a chemical
reaction, slopes are drawn at different times in the plot of concentration of
reactants versus time. The magnitude of slopes with increase of time
[NET June 2017]
(a) remains unchanged
(b) increases
(c) decreases
(d) increases and decreases periodically
Q5. The graph below plots the progress of
a dimerization reaction involving species A. It depicts a straight line with
slope k (the rate constant). What is the value of the intercept c in the graph?
[TIFR 2017]
(a) [A (0)]
(b) [A (0)]2
(c) [A (0)]-1
(d) k x [A (0)]2
Q6. The fraction of groups condensed at
time t in any stepwise condensation polymerization (overall second order
reaction) is
[NET Dec 2014]
Q7. Half life t1/2 for a third order reaction 3C → products, where Co is the initial concentration of C, will be
Q8. Experimentally determined rate law
for the chemical reaction
2 NO2F → 2 NO2 + F2 is R
= k [NO2F]
The rate determining step consistent with the rate law is
[NET June 2016]
(a) 2 NO2F → 2
NO2 + F2
(b) NO2F + F → NO2
+ F
(c) NO2F → NO2
+ F
(d) NO2 + F → NO2F
Q9. The concentration of a reactant R
varies with time for two different reactions as shown in the following plots:
[NET Dec 2015]
The
order of these two reactions I and II respectively are
(a) zero and one
(b) one and zero
(c) zero and two
(d) two and zero
Q10. Statement: Catalytic
decomposition of ammonia on platinum takes place at 1000oC
Reason: Ammonia is more strongly adsorbed
than hydrogen on platinum
Assertion: The rate law for the decomposition of
ammonia on platinum is given as,
[GATE 2001]
(a) both reason and assertion are correct
(b) both reason and assertion are wrong
(c) reason is correct but assertion is
wrong
(d) reason is wrong but assertion is
correct
Q11. Decomposition of ammonia
on tungsten at 850oC has a rate constant value of 0.10 Torr s-1.
If the initial pressure of ammonia is 100 Torr, the pressure of ammonia (in
torr) at t = 200s is
[GATE
2004]
(a) 10
(b) 20
(c) 50
(d) 80
Q12. Sucrose is converted to a
mixture of glucose and fructose in a pseudo first order process under alkaline
conditions. The reaction has a half-life of 28.4 min. The time required for the
reduction of a 8.0 mM sample of sucrose to 1.0 mM is
[GATE
2007]
(a) 56.8
min
(b) 170.4
min
(c) 85.2
min
(d) 227.2
min
Q13. The half-life time for a
reaction at initial concentration of 0.1 mol-1 and 0.4 mol-1
are 200 s and 50 s respectively. The order of the reaction is
[GATE
2000]
(a) 0
(b) 1
(c) 2
(d) 3
Q14. For a first order
reaction A → products, the plot of ln [A]t/[A]o
vs time, where [A]o and [A]t refer to concentration at
time t = 0 and t respectively is
[NET
June 2014]
(a) a
straight line with a positive slope passing through origin
(b) a
straight line with a negative slope passing through origin
(c) an
exponential curve asymptotic to the time axis
(d) a
curve asymptotic to the ln [A]t/[A]o axis
Q15. In the following reaction
mechanism
NO2 (g) + F2 (g) → NO2F
(g) + F (g)
F (g) + NO2 (g) → NO2F (g)
The first step, having a rate constant K1,
is very slow while the second step having a rate constant K2, is
very first. The rate law for this mechanism will therefore be
(a) Rate
= k1 [NO2] [F2]
(b) Rate
= k1k2 [NO2]2 [F2]2
(c) Rate
= k2 [NO2] [F]
(d) Rate
= k2 [NO2F] [F]
Q1.d Q2.c Q3.2000 Q4.c Q5.c Q6.c Q7.a Q8.c Q9.c Q10.NA Q11.d Q12.c Q13.c Q14.b Q15.a