Chemical Kinetics: JEE Mains Previous Year Questions (2021-2024) | Chemistry for JEE Main & Advanced PDF Download

 Page 1


 
 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The ratio of 
14
C
12
C
  in a piece of wood is 
1
8
 part that of atmosphere. If half life of
14
C is 
5730 years, the age of wood sample is  ______ years. 
Q2 - 2024 (01 Feb Shift 2) 
The following data were obtained during the first order thermal decomposition of a gas A 
at constant volume: 
A(g)? 2B(g) + C(g) 
S.No Time/s Total pressure /(atm) 
1. 0 0.1 
2. 115 0.28 
The rate constant of the reaction is _____ × 10
-2
s
-1
 (nearest integer) 
Q3 - 2024 (27 Jan Shift 1) 
Consider the following data for the given reaction 
2HI
(g)
? H
2(g)
+ I
2(g)
 
 1 2 3 
HI molL
-1
  0.005 0.01  0.02 
Rate  molL
-1
s- 1  7.5 × 10
-4
 3.0 × 10
-3
 1.2 × 10
-2
 
 
The order of the reaction is __ 
Page 2


 
 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The ratio of 
14
C
12
C
  in a piece of wood is 
1
8
 part that of atmosphere. If half life of
14
C is 
5730 years, the age of wood sample is  ______ years. 
Q2 - 2024 (01 Feb Shift 2) 
The following data were obtained during the first order thermal decomposition of a gas A 
at constant volume: 
A(g)? 2B(g) + C(g) 
S.No Time/s Total pressure /(atm) 
1. 0 0.1 
2. 115 0.28 
The rate constant of the reaction is _____ × 10
-2
s
-1
 (nearest integer) 
Q3 - 2024 (27 Jan Shift 1) 
Consider the following data for the given reaction 
2HI
(g)
? H
2(g)
+ I
2(g)
 
 1 2 3 
HI molL
-1
  0.005 0.01  0.02 
Rate  molL
-1
s- 1  7.5 × 10
-4
 3.0 × 10
-3
 1.2 × 10
-2
 
 
The order of the reaction is __ 
 
Q4 - 2024 (27 Jan Shift 2) 
Time required for completion of 99.9% of a First order reaction is __ times of half life 
 ?? 1/2
  of the reaction. 
Q5 - 2024 (29 Jan Shift 1) 
For a reaction taking place in three steps at same temperature, overall rate constant 
K =
K
1
K
2
K
3
. If Ea
1
, Ea
2
 and Ea
3
 are 40,50 and 60kJ/mol respectively, the overall Ea is 
______kJ/mol. 
 
Q6 - 2024 (29 Jan Shift 2) 
The half-life of radioisotopic bromine - 82 is 36 hours. The fraction which remains after 
one day ______ is × 10
-2
 
(Given antilog 0.2006 = 1.587) 
Q7 - 2024 (30 Jan Shift 1) 
The rate of first order reaction is 0.04 molL
-1
s
-1
 at 10 minutes and 0.03 molL
-1
s
-1
 at 20 
minutes after initiation. Half life of the reaction is minutes. (Given log2 = 0.3010, log3 =
0.4771) 
Q8 - 2024 (30 Jan Shift 2) 
NO
2 
required for a reaction is produced by decomposition of N
2
O
5
 in CCl
4
 as by equation 
2N
2
O
5
(g)? 4NO
2
(g) + O
2
(g) 
The initial concentration of N
2
O
5
 is 3mol L
-1
 and it is 2.75mol L
-1
 after 30 minutes. 
The rate of formation of NO
2
 is x × 10
-3
mol L
-1
min
-1
, value of x is 
Q9 - 2024 (31 Jan Shift 1) 
Integrated rate law equation for a first order gas phase reaction is given by (where ?? ?? is 
initial pressure and P
t
 is total pressure at time t) 
(1) k =
2.303
t
× log
P
i
 2P
i
-P
t
 
 
(2) k =
2.303
t
× log
2P
i
 2P
i
-P
t
 
 
(3) k =
2.303
t
× log
 2P
i
-P
t
 
P
i
 
(4) ?? =
2.303
?? ×
?? ?? 2?? ?? -?? ?? 
 
Page 3


 
 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The ratio of 
14
C
12
C
  in a piece of wood is 
1
8
 part that of atmosphere. If half life of
14
C is 
5730 years, the age of wood sample is  ______ years. 
Q2 - 2024 (01 Feb Shift 2) 
The following data were obtained during the first order thermal decomposition of a gas A 
at constant volume: 
A(g)? 2B(g) + C(g) 
S.No Time/s Total pressure /(atm) 
1. 0 0.1 
2. 115 0.28 
The rate constant of the reaction is _____ × 10
-2
s
-1
 (nearest integer) 
Q3 - 2024 (27 Jan Shift 1) 
Consider the following data for the given reaction 
2HI
(g)
? H
2(g)
+ I
2(g)
 
 1 2 3 
HI molL
-1
  0.005 0.01  0.02 
Rate  molL
-1
s- 1  7.5 × 10
-4
 3.0 × 10
-3
 1.2 × 10
-2
 
 
The order of the reaction is __ 
 
Q4 - 2024 (27 Jan Shift 2) 
Time required for completion of 99.9% of a First order reaction is __ times of half life 
 ?? 1/2
  of the reaction. 
Q5 - 2024 (29 Jan Shift 1) 
For a reaction taking place in three steps at same temperature, overall rate constant 
K =
K
1
K
2
K
3
. If Ea
1
, Ea
2
 and Ea
3
 are 40,50 and 60kJ/mol respectively, the overall Ea is 
______kJ/mol. 
 
Q6 - 2024 (29 Jan Shift 2) 
The half-life of radioisotopic bromine - 82 is 36 hours. The fraction which remains after 
one day ______ is × 10
-2
 
(Given antilog 0.2006 = 1.587) 
Q7 - 2024 (30 Jan Shift 1) 
The rate of first order reaction is 0.04 molL
-1
s
-1
 at 10 minutes and 0.03 molL
-1
s
-1
 at 20 
minutes after initiation. Half life of the reaction is minutes. (Given log2 = 0.3010, log3 =
0.4771) 
Q8 - 2024 (30 Jan Shift 2) 
NO
2 
required for a reaction is produced by decomposition of N
2
O
5
 in CCl
4
 as by equation 
2N
2
O
5
(g)? 4NO
2
(g) + O
2
(g) 
The initial concentration of N
2
O
5
 is 3mol L
-1
 and it is 2.75mol L
-1
 after 30 minutes. 
The rate of formation of NO
2
 is x × 10
-3
mol L
-1
min
-1
, value of x is 
Q9 - 2024 (31 Jan Shift 1) 
Integrated rate law equation for a first order gas phase reaction is given by (where ?? ?? is 
initial pressure and P
t
 is total pressure at time t) 
(1) k =
2.303
t
× log
P
i
 2P
i
-P
t
 
 
(2) k =
2.303
t
× log
2P
i
 2P
i
-P
t
 
 
(3) k =
2.303
t
× log
 2P
i
-P
t
 
P
i
 
(4) ?? =
2.303
?? ×
?? ?? 2?? ?? -?? ?? 
 
Q10 - 2024 (31 Jan Shift 2) 
r = k A  for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% 
decomposition of A is _____ minutes. 
Answer Key 
Q1 (17190) 
Q2 (2) 
Q3 (2) 
Q4 (10) 
Q5 (30) 
Q6 (63) 
Q7 (24) 
Q8 (17) 
Q9 (1) 
Q10 (399) 
 
Solutions 
Q1 
 
 
Q2 
Page 4


 
 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The ratio of 
14
C
12
C
  in a piece of wood is 
1
8
 part that of atmosphere. If half life of
14
C is 
5730 years, the age of wood sample is  ______ years. 
Q2 - 2024 (01 Feb Shift 2) 
The following data were obtained during the first order thermal decomposition of a gas A 
at constant volume: 
A(g)? 2B(g) + C(g) 
S.No Time/s Total pressure /(atm) 
1. 0 0.1 
2. 115 0.28 
The rate constant of the reaction is _____ × 10
-2
s
-1
 (nearest integer) 
Q3 - 2024 (27 Jan Shift 1) 
Consider the following data for the given reaction 
2HI
(g)
? H
2(g)
+ I
2(g)
 
 1 2 3 
HI molL
-1
  0.005 0.01  0.02 
Rate  molL
-1
s- 1  7.5 × 10
-4
 3.0 × 10
-3
 1.2 × 10
-2
 
 
The order of the reaction is __ 
 
Q4 - 2024 (27 Jan Shift 2) 
Time required for completion of 99.9% of a First order reaction is __ times of half life 
 ?? 1/2
  of the reaction. 
Q5 - 2024 (29 Jan Shift 1) 
For a reaction taking place in three steps at same temperature, overall rate constant 
K =
K
1
K
2
K
3
. If Ea
1
, Ea
2
 and Ea
3
 are 40,50 and 60kJ/mol respectively, the overall Ea is 
______kJ/mol. 
 
Q6 - 2024 (29 Jan Shift 2) 
The half-life of radioisotopic bromine - 82 is 36 hours. The fraction which remains after 
one day ______ is × 10
-2
 
(Given antilog 0.2006 = 1.587) 
Q7 - 2024 (30 Jan Shift 1) 
The rate of first order reaction is 0.04 molL
-1
s
-1
 at 10 minutes and 0.03 molL
-1
s
-1
 at 20 
minutes after initiation. Half life of the reaction is minutes. (Given log2 = 0.3010, log3 =
0.4771) 
Q8 - 2024 (30 Jan Shift 2) 
NO
2 
required for a reaction is produced by decomposition of N
2
O
5
 in CCl
4
 as by equation 
2N
2
O
5
(g)? 4NO
2
(g) + O
2
(g) 
The initial concentration of N
2
O
5
 is 3mol L
-1
 and it is 2.75mol L
-1
 after 30 minutes. 
The rate of formation of NO
2
 is x × 10
-3
mol L
-1
min
-1
, value of x is 
Q9 - 2024 (31 Jan Shift 1) 
Integrated rate law equation for a first order gas phase reaction is given by (where ?? ?? is 
initial pressure and P
t
 is total pressure at time t) 
(1) k =
2.303
t
× log
P
i
 2P
i
-P
t
 
 
(2) k =
2.303
t
× log
2P
i
 2P
i
-P
t
 
 
(3) k =
2.303
t
× log
 2P
i
-P
t
 
P
i
 
(4) ?? =
2.303
?? ×
?? ?? 2?? ?? -?? ?? 
 
Q10 - 2024 (31 Jan Shift 2) 
r = k A  for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% 
decomposition of A is _____ minutes. 
Answer Key 
Q1 (17190) 
Q2 (2) 
Q3 (2) 
Q4 (10) 
Q5 (30) 
Q6 (63) 
Q7 (24) 
Q8 (17) 
Q9 (1) 
Q10 (399) 
 
Solutions 
Q1 
 
 
Q2 
 
 
Q3 
Let, R = k[HI]
n
 
using any two of given data, 
3 × 10
-3
7.5 × 10
-4
= 
0.01
0.005
 
n
 
n = 2 
 
Q4 
t
99.9%
t
1/2
=
2.303
k
 
a
a-x
 
2.303
k
log2
=
log 
100
100-99.9
 
log2
=
log10
3
log2
=
3
0.3
= 10 
 
Q5 
?? =
?? 1
·?? 2
?? 3
=
?? 1
·?? 2
?? 3
·?? -
 ?? 
?? 1
+?? ?? 2
-?? ?? 3
 
?? ?? 
?? ?? 
?? ·?? -?? ?? /?? ?? =
?? 1
?? 2
?? 3
·?? -
 ?? ?? 1
+?? 2
-?? ?? 3
 
?? ?? 
E
a
= E
a
1
+ E
a
2
- E
a
3
= 40 + 50- 60 = 30kJ/mole 
 
Q6 
Half life of bromine -82 = 36 hours 
Page 5


 
 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The ratio of 
14
C
12
C
  in a piece of wood is 
1
8
 part that of atmosphere. If half life of
14
C is 
5730 years, the age of wood sample is  ______ years. 
Q2 - 2024 (01 Feb Shift 2) 
The following data were obtained during the first order thermal decomposition of a gas A 
at constant volume: 
A(g)? 2B(g) + C(g) 
S.No Time/s Total pressure /(atm) 
1. 0 0.1 
2. 115 0.28 
The rate constant of the reaction is _____ × 10
-2
s
-1
 (nearest integer) 
Q3 - 2024 (27 Jan Shift 1) 
Consider the following data for the given reaction 
2HI
(g)
? H
2(g)
+ I
2(g)
 
 1 2 3 
HI molL
-1
  0.005 0.01  0.02 
Rate  molL
-1
s- 1  7.5 × 10
-4
 3.0 × 10
-3
 1.2 × 10
-2
 
 
The order of the reaction is __ 
 
Q4 - 2024 (27 Jan Shift 2) 
Time required for completion of 99.9% of a First order reaction is __ times of half life 
 ?? 1/2
  of the reaction. 
Q5 - 2024 (29 Jan Shift 1) 
For a reaction taking place in three steps at same temperature, overall rate constant 
K =
K
1
K
2
K
3
. If Ea
1
, Ea
2
 and Ea
3
 are 40,50 and 60kJ/mol respectively, the overall Ea is 
______kJ/mol. 
 
Q6 - 2024 (29 Jan Shift 2) 
The half-life of radioisotopic bromine - 82 is 36 hours. The fraction which remains after 
one day ______ is × 10
-2
 
(Given antilog 0.2006 = 1.587) 
Q7 - 2024 (30 Jan Shift 1) 
The rate of first order reaction is 0.04 molL
-1
s
-1
 at 10 minutes and 0.03 molL
-1
s
-1
 at 20 
minutes after initiation. Half life of the reaction is minutes. (Given log2 = 0.3010, log3 =
0.4771) 
Q8 - 2024 (30 Jan Shift 2) 
NO
2 
required for a reaction is produced by decomposition of N
2
O
5
 in CCl
4
 as by equation 
2N
2
O
5
(g)? 4NO
2
(g) + O
2
(g) 
The initial concentration of N
2
O
5
 is 3mol L
-1
 and it is 2.75mol L
-1
 after 30 minutes. 
The rate of formation of NO
2
 is x × 10
-3
mol L
-1
min
-1
, value of x is 
Q9 - 2024 (31 Jan Shift 1) 
Integrated rate law equation for a first order gas phase reaction is given by (where ?? ?? is 
initial pressure and P
t
 is total pressure at time t) 
(1) k =
2.303
t
× log
P
i
 2P
i
-P
t
 
 
(2) k =
2.303
t
× log
2P
i
 2P
i
-P
t
 
 
(3) k =
2.303
t
× log
 2P
i
-P
t
 
P
i
 
(4) ?? =
2.303
?? ×
?? ?? 2?? ?? -?? ?? 
 
Q10 - 2024 (31 Jan Shift 2) 
r = k A  for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% 
decomposition of A is _____ minutes. 
Answer Key 
Q1 (17190) 
Q2 (2) 
Q3 (2) 
Q4 (10) 
Q5 (30) 
Q6 (63) 
Q7 (24) 
Q8 (17) 
Q9 (1) 
Q10 (399) 
 
Solutions 
Q1 
 
 
Q2 
 
 
Q3 
Let, R = k[HI]
n
 
using any two of given data, 
3 × 10
-3
7.5 × 10
-4
= 
0.01
0.005
 
n
 
n = 2 
 
Q4 
t
99.9%
t
1/2
=
2.303
k
 
a
a-x
 
2.303
k
log2
=
log 
100
100-99.9
 
log2
=
log10
3
log2
=
3
0.3
= 10 
 
Q5 
?? =
?? 1
·?? 2
?? 3
=
?? 1
·?? 2
?? 3
·?? -
 ?? 
?? 1
+?? ?? 2
-?? ?? 3
 
?? ?? 
?? ?? 
?? ·?? -?? ?? /?? ?? =
?? 1
?? 2
?? 3
·?? -
 ?? ?? 1
+?? 2
-?? ?? 3
 
?? ?? 
E
a
= E
a
1
+ E
a
2
- E
a
3
= 40 + 50- 60 = 30kJ/mole 
 
Q6 
Half life of bromine -82 = 36 hours 
t
1/2
=
0.693
K
 
K =
0.693
36
= 0.01925hr
-1
 
1
st 
orderrxn kinetic equation 
?? =
2.303
?? log
?? ?? -?? 
log
a
a-x
=
t×K
2.303
(t = 1day= 24hr) 
log
a
a- x
=
24hr × 0.01925hr
-1
2.303
 
log
a?? h
a- x
= 0.2006 
a
a- x
= antilog(0.2006) 
a
a- x
= 1.587 
If a = 1 
1
1-x
= 1.587 ? 1- x = 0.6301 = Fraction remain after one day 
 
Q7 
 
4
3
= e
600k (2-1)
 
4
3
= e
600k
 
ln
4
3
= 600k 
ln
4
3
= 600 ×
ln2
t
1/2
 
t
1/2
= 600
ln2
ln
4
3
sec