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Chemical Kinetics

75 Questions
All Exams NEET AIIMS
2010 NEET MCQ
AIPMT 2010 Prelims
During the kinetic study of the reaction, 2A + B $ \to $ C + D, following results were obtained
Run [A]/mol L$-$1 [B]/mol L$-$1 Initial rate of formation
of D/mol L$-$1 min$-$1
I. 0.1 0.1 6.0$ \times $10$-$3
II. 0.3 0.2 7.2$ \times $10$-$2
III. 0.3 0.4 2.88$ \times $10$-$1
IV. 0.4 0.1 2.40$ \times $10$-$2

Based on the above data which one of the following is correct?
A.
Rate = k[A]2[B]
B.
Rate = k[A][B]
C.
Rate = k[A]2[B]2
D.
Rate = k[A][B]2
2010 NEET MCQ
AIPMT 2010 Prelims
For the reaction N2O5(g) $ \to $  2NO2(g) + 1/2O2(g)
the value of rate of disappearance of N2O5 is given as 6.25 $ \times $ 10$-$3 mol L$-$1 s$-$1. The rate of formation of NO2 and O2 is given respectively as
A.
6.25 $ \times $ 10$-$3 mol L$-$1 s$-$1 and
6.25 $ \times $ 10$-$3 mol L$-$1 s$-$1
B.
1.25 $ \times $ 10$-$2 mol L$-$1 s$-$1 and
3.125 $ \times $ 10$-$3 mol L$-$1 s$-$1
C.
6.25 $ \times $ 10$-$3 mol L$-$1 s$-$1 and
3.125 $ \times $ 10$-$3 mol L$-$1 s$-$1
D.
1.25 $ \times $ 10$-$2 mol L$-$1 s$-$1 and
6.25 $ \times $ 10$-$3 mol L$-$1 s$-$1
2009 NEET MCQ
AIPMT 2009
For the reaction, N2 + 3H2 $ \to $ 2NH3, if
${{d\left[ {N{H_3}} \right]} \over {dt}}$ = 2 $ \times $ 10$-$4 mol L$-$1 s$-$1,
the value of ${{ - d\left[ {{H_2}} \right]} \over {dt}}$ would be
A.
4 $ \times $ 10$-$4 mol L$-$1 s$-$1
B.
6 $ \times $ 10$-$4 mol L$-$1 s$-$1
C.
1 $ \times $ 10$-$4 mol L$-$1 s$-$1
D.
3 $ \times $ 10$-$4 mol L$-$1 s$-$1
2009 NEET MCQ
AIPMT 2009
In the reaction,
BrO$_{3(aq)}^ - $ + 5Br$_{(aq)}^ - $ + 6H+ $ \to $ 3Br2(l) + 3H2O(l).
The rate of appearance of bromine (Br2) is related to rate of disappearance of bromide ions as
A.
${{d\left[ {B{r_2}} \right]} \over {dt}} = - {5 \over 3}{{d\left[ {B{r^ - }} \right]} \over {dt}}$
B.
${{d\left[ {B{r_2}} \right]} \over {dt}} = {5 \over 3}{{d\left[ {B{r^ - }} \right]} \over {dt}}$
C.
${{d\left[ {B{r_2}} \right]} \over {dt}} = {3 \over 5}{{d\left[ {B{r^ - }} \right]} \over {dt}}$
D.
${{d\left[ {B{r_2}} \right]} \over {dt}} = - {3 \over 5}{{d\left[ {B{r^ - }} \right]} \over {dt}}$
2009 NEET MCQ
AIPMT 2009
For the reaction A + B $ \to $ products, it is observed that

(i)  on doubling the initial concentration of A only, the rate of reaction is also doubled and
(ii)  on doubling the initial concentration of both A and B, there is a change by a factor of 8 in the rate of the reaction.

The rate of this reaction is given by
A.
rate = k[A]2 [B]2
B.
rate = k[A] [B]2
C.
rate = k[A] [B]
D.
rate = k[A]2 [B]
2009 NEET MCQ
AIPMT 2009
Half-life period of a first order reaction is 1386 seconds. The specific rate constant of the reaction is
A.
0.5 $ \times $ 10$-$2 s$-$1
B.
0.5 $ \times $ 10$-$3 s$-$1
C.
5.0 $ \times $ 10$-$2 s$-$1
D.
5.0 $ \times $ 10$-$3 s$-$1.
2008 NEET MCQ
AIPMT 2008
The rate constants k1 and k2 for two different reactions are 1016 $ \cdot $ e$-$2000/T and 1015 $ \cdot $ e$-$1000/T, respectively.
The temperature at which k1 = k2 is
A.
2000 K
B.
${{1000} \over {2.303}}K$
C.
1000 K
D.
${{2000} \over {2.303}}K$
2008 NEET MCQ
AIPMT 2008
The bromination of acetone that occurs in acid solution is represented by this equation.
CH3COCH3(aq) + Br2(aq)  $ \to $
     CH3COCH2Br(aq) + H+(aq) + Br$-$(aq)
These kinetic data were obtained for given reaction concentrations.
Initial concentrations, M
[CH3COCH3 [Br2] [H+]
0.30 0.05 0.05
0.30 0.10 0.05
0.30 0.10 0.10
0.40 0.05 0.20

Initial rate, disappearance of Br2, Ms$-$1
5.7$ \times $10$-$5
5.7$ \times $10$-$5
1.2$ \times $10$-$4
3.1$ \times $10$-$4

Based on these data, the rate equation is
A.
Rate = k[CH3COCH3][Br2][H+]2
B.
Rate = k[CH3COCH3][Br2][H+]
C.
Rate = k[CH3COCH3][H+]
D.
Rate = k[CH3COCH3][Br2]
2007 NEET MCQ
AIPMT 2007
The reaction of hydrogen and iodine monochloride is given as :
H2(g) + 2ICl(g) $ \to $ 2HCl(g) + I2(g)
This reaction is of first order with respect to H2(g) and ICl(g),
following mechanisms were proposed.

Mechanism A :
     H2(g) + 2ICl(g) $ \to $ 2HCl(g) + I2(g)
Mechanism B :
     H2(g) + ICl(g) $ \to $ HCl(g) + HI(g) ; slow
     HI(g) + ICl(g) $ \to $ HCl(g) + I2(g) ; fast

Which of the above mechanism(s) can be consistent with the given information about the reaction?
A.
A and B both
B.
Neither A nor B
C.
A only
D.
B only
2007 NEET MCQ
AIPMT 2007
In a first-order reaction A $ \to $ B, if k is rate constant and initial concentration of the reactant A is 0.5 M, then the half-life is
A.
${{\log 2} \over k}$
B.
${{\log 2} \over {k\sqrt {0.5} }}$
C.
${{\ln 2} \over k}$
D.
${{0.693} \over {0.5k}}$
2007 NEET MCQ
AIPMT 2007
If 60% of a first order reaction was completed in 60 minutes, 50% of the same reaction would be completed in approximately
(log 4 = 0.60, log 5 = 0.69)
A.
45 minutes
B.
60 minutes
C.
40 minutes
D.
50 minutes
2006 NEET MCQ
AIPMT 2006
For the reaction, 2A + B $ \to $ 3C + D, which of the following does not express the reaction rate?
A.
$ - {{d\left[ A \right]} \over {2dt}}$
B.
$ - {{d\left[ C \right]} \over {3dt}}$
C.
$ - {{d\left[ B \right]} \over {dt}}$
D.
$ {{d\left[ D \right]} \over {dt}}$
2006 NEET MCQ
AIPMT 2006
Consider the reaction :  N2(g) + 3H2(g) $ \to $ 2NH3(g)

The equality relationship between ${{d\left[ {N{H_3}} \right]} \over {dt}}$ and $ - {{d\left[ {{H_2}} \right]} \over {dt}}$ is
A.
${{d\left[ {N{H_3}} \right]} \over {dt}} = - {{d\left[ {{H_2}} \right]} \over {dt}}$
B.
${{d\left[ {N{H_3}} \right]} \over {dt}} = - {1 \over 3}{{d\left[ {{H_2}} \right]} \over {dt}}$
C.
$ + {{d\left[ {N{H_3}} \right]} \over {dt}} = - {2 \over 3}{{d\left[ {{H_2}} \right]} \over {dt}}$
D.
$ + {{d\left[ {N{H_3}} \right]} \over {dt}} = - {3 \over 2}{{d\left[ {{H_2}} \right]} \over {dt}}$
2005 NEET MCQ
AIPMT 2005
The rate of reaction between two reactions A and B decreases by a factor of 4 if the concentration of reactant B is doubled. The order of this reaction with respect to reactant B is
A.
2
B.
$-$2
C.
1
D.
$-$1
2005 NEET MCQ
AIPMT 2005
For a first order reaction A $ \to $ B the reaction rate a reactant concentration of 0.01 M is found to be 2.0 $ \times $ 10$-$5 mol L$-$1 s$-$1. The half-life period of the reaction is
A.
30 s
B.
220 s
C.
300 s
D.
347 s
2004 NEET MCQ
AIPMT 2004
The rate of a first order reaction is 1.5 $ \times $ 10$-$2 mol L$-$1 min$-$1 at 0.5 M concentration of the reactant. The half-life of the reaction is
A.
0.383 min
B.
23.1 min
C.
8.73 min
D.
7.53 min
2003 NEET MCQ
AIPMT 2003
The reaction A $ \to $ B follows first order kinetics. The time taken for 0.8 mole of A to produce 0.6 mole of B is 1 hour. What is the time taken for conversion of 0.9 mole of A to produce 0.675 mole of B?
A.
1 hour
B.
0.5 hour
C.
0.25 hour
D.
2 hours
2003 NEET MCQ
AIPMT 2003
The temperature dependence of rate constant (k) of a chemical reaction is written in terms of Arrhenius equation, $k = A \cdot {e^{ - E{}^ * /RT}}$. Activation energy (E$ * $) of the reaction can be calculated by plotting
A.
$k\,\,vs\,\,T$
B.
$k\,\,vs\,\,{1 \over {\log T}}$
C.
$\log \,k\,\,vs\,\,{1 \over T}$
D.
$\log \,k\,\,vs\,{1 \over {\log T}}$
2003 NEET MCQ
AIPMT 2003
The activation energy for a simple chemical reaction A $\rightleftharpoons$ B is E$a$ in forward direction.
The activation energy for reverse reaction
A.
is negative of E$a$
B.
is always less than E$a$
C.
can be less than or more than E$a$
D.
is always double of E$a$
2003 NEET MCQ
AIPMT 2003
If the rate of the reaction is equal to the rate constant, the order of the reaction is
A.
0
B.
1
C.
2
D.
3
2002 NEET MCQ
AIPMT 2002
2A $ \to $ B + C

It would be a zero order reaction when
A.
the rate of reaction is proportional to square of concentration of A
B.
The rate of reaction remains same at any concentration of A
C.
the rate remains unchanged at any concentration of B and C
D.
the rate of reaction doubles if concentrations of B is increased to double.
2001 NEET MCQ
AIPMT 2001
For the reaction;

2N2O5 $ \to $ 4NO2 + O2 rate and rate constant are 1.02 $ \times $ 10$-$4 and 3.4 $ \times $ 10$-$5 sec$-$1 respectively, then concentration of N2O5 at that time will be
A.
1.732
B.
3
C.
1.02 $ \times $ 10$-$4
D.
3.4 $ \times $ 105
2001 NEET MCQ
AIPMT 2001
When a bio-chemical reaction is carried out in laboratory, outside the human body in absence of enzyme, then rate of reaction obtained is 10$-$6 times, the activation energy of reaction in the presence of enzyme is
A.
6/RT
B.
P is required
C.
different from E$a$ obtained in laboratory
D.
can't say anything.
2000 NEET MCQ
AIPMT 2000
For the reaction H+ + BrO$_3^ - $ + 3Br$-$ $ \to $ 5Br2 + H2O
which of the following relation correctly represents the consumption and formation of products.
A.
${{d\left[ {B{r^ - }} \right]} \over {dt}} = - {3 \over 5}{{d\left[ {B{r_2}} \right]} \over {dt}}$
B.
${{d\left[ {B{r^ - }} \right]} \over {dt}} = {3 \over 5}{{d\left[ {B{r_2}} \right]} \over {dt}}$
C.
${{d\left[ {B{r^ - }} \right]} \over {dt}} = - {5 \over 3}{{d\left[ {B{r_2}} \right]} \over {dt}}$
D.
${{d\left[ {B{r^ - }} \right]} \over {dt}} = {5 \over 3}{{d\left[ {B{r_2}} \right]} \over {dt}}$
2000 NEET MCQ
AIPMT 2000
How enzymes increases the rate of reactions
A.
by lowering activation energy
B.
by increaing activation energy
C.
by changing equilibrium constant
D.
by forming enzyme substrate complex.