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FINAL REVISION & PRACTICE CHEMISTRY XII CBSE 2022
UNIT: 2:- CHEMICAL KINETICS
1
...

2
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For the reaction R →P, the concentration of a reactant changes from 0
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02M in 25 minutes
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4
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5mol L-1 to 0
...

Calculate the rate during this interval?
5
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8 x 10-3Ms-1
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For the reaction H2 + Cl2 → 2 HCl , Rate = k ,Write the order,Molecularity & unit of k
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For the reaction 2NH3 → N2+ 3H2 Rate = k ,Write the order,Molecularity & unit of k
...
The decomposition of N2O5 in CCl4 at 318K has been studied by monitoring the concentration of N2O5 in the
solution
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33 mol L–1 and after 184 minutes, it is reduced to 2
...

The reaction takes place according to the equation 2 N2O5 (g) → 4 NO2 (g) + O2 (g)
...
What is the rate of production of NO 2 during this period?
9
...
Define rate constant
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Write a short note on Order of reaction
...

11
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For a reaction, A + B → product, the rate law is given by r = K [A]1/2 [B]2 what is the order of the reaction?
13
...

14
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If the concentration of x is increased to three
times, how will it affect the rate of formation of y?
15
...
Identify the reaction order from of the following rate constants
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3 x 10-5 L mol-1s-1 (ii) k = 3 x10-4 s-1
17
...
a) H2O2 (aq) + 3 I - (aq) + 2H+ → 2H2O (l) + 3I-1
Rate = k [H2O] [I-] b) CH3 CHO (g) →CH4(g) + CO(g)
3/2
2
Rate = k [CH3 CHO]
c)3NO→N2O (g) Rate = k [NO]
d)C2H5Cl→C2H4 + HCl Rate = k[C2H5 Cl]
18
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5 x 10-4 mol L-1 S-1
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For the reaction: 2A + B → A2B the rate = k[A][B]2 with k = 2
...
Calculate the initial rate of the
reaction when [A] = 0
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2 mol L–1
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06 mol L–
1

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A reaction is first order in A and second order in B
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ii) How is the rate affected when concentration of B is tripled?
iii) How is the rate affected when the concentration of both A and B is doubled?
21
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How is the rate of reaction affected if the concentration of
the reactant is(i) doubled (ii) reduced to half ?
22
...
What is the
order of reaction?
23
...
What is the order of the reaction ?
24
...
If the concentration of x is increased to three
times, how will it affect the rate of formation of y?
25
...
What is the order of the reaction ?
26
...
What is the order of the reaction ?
27
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What are the rates of production of N 2 and
H2 if k = 2
...
The decomposition of dimethyl ether leads to the formation of CH4, H2 and CO and the reaction rate is given by
Rate = k [CH3 CHO]3/2 The rate of reaction is followed by increase in pressure in a closed vessel, so the rate can
MAHENDRA KALRA

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also be expressed in terms of the partial pressure of dimethyl ether, i
...
, Rate = k (pCH3 CHO)3/2 If the pressure is
measured in bar and time in minutes, then what are the units of rate and rate constants?
29
...

30
...
Distinguish between order of reaction & Molecularity
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For which type of reactions, order and molecularity have the same value?
33
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Can the reaction be an elementary reaction? Explain
35
...

36
...
Why molecularity is applicable only for elementary reactions and order is applicable for elementary as well as
complex reactions?
38
...
Mention the factors that affect the rate of a chemical reaction
...
The possible mechanism for the reaction : 2NO (g) + O2 (g) → 2NO2 (g) is
K
2
(i)
NO + O2
NO3 (fast)
(II) NO3 + NO ⎯K⎯→
NO2 + NO2 (g) (slow)
...
For a reaction 2H2O2 ⎯I⎯
⎯⎯→ 2H2O + O2 the proposed mechanism is as follows
(i) H2O2 + I– → H2O + IO– (slow) (ii) H2O2 + IO–→ H2O + I– + O2 (fast)
(a)Write the rate law for the reaction
...

(iii)Out of steps (i) & (ii) which one is rate determining step
...
For a chemical reaction A + 2B → 2C + D
...

Experiment
[A]0
[B]0
Initial rate
-

1
0
...
30
0
...
60
0
...
384
3
0
...
60
0
...
60
0
...
768
(i)Derive the order of reaction w
...
t
...
(ii) Write the rate law
...

43
...
1
0
...
0 x 10-3
II
0
...
2
7
...
3
0
...
88 x 10-1
IV
0
...
1
2
...
The reaction between A and B is first order with respect to A and zero order with respect to B
...
1
0
...
0 × 10–2
II
–
0
...
0 × 10–2
III
0
...
4
–
IV
–
0
...
0 × 10–2
45
...
20
0
...
40
–1
B/ mol L
0
...
10
0
...
07 × 10
5
...
43 × 10–4
What is the order of the reaction with respect to A and B?
46
...
Find half life period and plot the graph associated to
it
...
For a zero order chemical reaction: (a) Plot variation in the concentration in [R] vs
...
(b) what are the units of
rate constant k? (c) give the relationship between k and t ½ (half life period) (d) Give the slope
MAHENDRA KALRA
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48
...
In how much
time will the reaction go to completion?
49
...
0030molL-1s-1
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10 M to 0
...
The decomposition of NH3 on platinum surface is zero order reaction
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1M to 0
...

51
...
Find half life period and plot the graph associated to
it
...
For a first order chemical reaction:(i) Plot variation in the concentration in ln[R] vs
...
time t(s) & Give the slope (iii) what are the units of rate constant k?(iv) give the
relationship between k and t ½ (half life period) (iv) Give the slope
53
...
What is the
order of reaction
...
(a) Define half life period of a reaction
...
What are pseudo first order reactions? Give one example of such reaction
...
A first order reaction has rate constant 1
...
How long will 5 g of this reactant take to reduce to 3 g?
57
...
If the decomposition is a first order
reaction, calculate the rate constant of the reaction
...
The initial concentration of N2O5 in the following first order reaction N2O5(g) → NO2(g) + 1/2O2 (g) was 1
...
The concentration of N2O5 after 60 minutes was 0
...
Calculate the rate constant
of the reaction at 318 K
...
A first order reaction is found to have a rate constant
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5 x 10-4 s-1
...

60
...
9% is 10 times of half-life (t1/2) of the
reaction
...
For a first order reaction, show that time required for 99% completion is twice the time required for the
completion of 90% of reaction
...
Calculate the half-life of a first order reaction from their rate constants given : (i) 200 s–1 (ii) 2 min–1 (iii) 4 years–
1

...
The half-life for radioactive decay of 14C is 5730 years
...
Estimate the age of the sample
64
...
How much time will it take to reduce the initial
concentration of the reactant to its 1/16th value?
65
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1 years
...

66
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06 x 10-3 min-1
...

67
...
Calculate the time required for 90% completion
for this reaction
68
...
Calculate the time required for 90% completion
for this reaction
69
...
Calculate the time required for 75% completion
for this reaction
70
...
Calculate t 1/2
...
Consider a certain reaction A→ Products with k = 2
...
Calculate the concentration of A remaining after
100 s if the initial concentration of A is 1
...

72
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00 hours
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A first order reaction has a rate constant 0
...
If we begin with 0
...

74
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(i)Calculate the rate constant for the first order reaction
(ii) what fraction of the reactant will be left after an hour of the reaction has occurred
...
The decomposition of phosphine PH3 proceeds according to the following equation: 4PH3→P4 + 6H2 ,It is found
that the reaction follows rate reaction rate=K[PH3] The half life of PH3 is 37
...

(i)How much time is required for 3/4th of PH3 to decompose? (ii)What fraction of the original sample of PH3
remains behind after 1 minute?
76
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How are t1 and t 2 related ?

77
...

Calculate the rate constant
...
0
360
54
...
0
78
...
Calculate the rate constant
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4
2
100
0
...
The following data were obtained during the first order thermal decomposition of N2O5 (g) at constant volume:
2N2O5(g)→2N2O4(g) + O2(g)
...

S
...
5
2
100
0
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Following data were obtained for the reaction : N2O5(g)→2NO2(g) +1/2 O2(g)
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6 x 10
0
...
4 x 10-2
(mol/l)
(i)
Show that it follows first order reaction
(ii)Calculate the half life
81
...
55
0
...
17
0
...
(ii) Calculate the pseudo first order
rate constant for the hydrolysis of ester

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