12th Chemistry Monthly Test - 1 ( Chemical Kinetics )

St. Britto Hr. Sec. School - Madurai

12th Chemistry Monthly Test - 1 ( Chemical Kinetics )-Aug 2020

Time : 2.30 Hours

Part - A

Multiple Choice Question - Answer All Question

If 75% of a first order reaction was completed in 60 minutes , 50% of the same reaction under the same conditions would be completed in

20 minutes
30 minutes
35 minutes
75 minutes

Energy of activation of a reactant is reduced by ___________

reduced pressure
increased pressure
reduced temperature
increased temperature

Arrhenius equation is

k = Ae^-1/RT
k = Ae^RT/E_a
k = Ae^-E_a/ ^RT
k = Ae^Ea^/RT

During a chemical reaction, the concentration of reaction

increases
decreases
remains constant
first increases and then decreases

For the reaction, 2NH₃ ⟶ N₂ + 3H₂, if \(\frac { -d[NH_{ 3 }] }{ dt } \)=k₁[NH₃], \(\frac { d[N_{ 2 }] }{ dt } =k_{ 2 }[NH_{ 3 }],\frac { d[{ H }_{ 2 }] }{ dt } \)=k₃[NH₃] then the relation between k₁, k₂ and k₃ is

k₁=k₂=k₃
k₁=3k₂=2k₃
1.5k₁=3k₂=k₃
2k₁=k₂=3k₃

In any unimolecular reaction _______________

Only two reacting species is involved in the rate determining step.
The order and the molecularity of slowest step are equal to one.
The molecularity of the reaction is one and order is zero.
Both molecularity and order of the reaction are one.

Activation energy is equal to _____________

Threshold energy + Energy of colloding molecules
Threshold energy
Threshold energy x Energy of colloiding molecules
Threshold energy - Energy of colloiding molecules

After 2 hours, a radioactive substance becomes \(\left( \cfrac { 1 }{ 16 } \right) ^{ th }\) of original amount Then the half life ( in min) is

60 minutes
120 minutes
30 minutes
15 minutes

The given reaction
2 FeCl₃ + SnCl₂ ⟶ 2FeCl₂ + SnCl₄ is an example of

I order
II order
III order
None of these

The time required for 50%completion of the reaction is known as ___________

Average life period
Half-life period
Rate
None of these

Nitric oxide (NO) reacts wtih oxygen to produce nitrogen dioxide
2NO_(g) + O_2(g) ⟶ 2NO_2(g)
If the mechanism of reaction is
NO + O₂ \(\overset { K }{ \rightleftharpoons } \) NO₃ (fast)
NO₃ + NO \(\overset { { K }_{ 1 } }{ \rightleftharpoons } \) NO₂ + NO₂ (slow)

Rate = K' [NO] [O₂]
Rate = K' [NO] [O₂]₂
Rate = K' [NO]² [O₂]
Rate = K' [NO]³ [O₂]

In a first order reaction \(x\longrightarrow y\) if k is the rate constant and the initial concentration of the reactant x is 0.1M, then, the half life is

\(\left( \cfrac { log2 }{ k } \right) \)
\(\left( \cfrac { 0.693 }{ (0.1)k } \right) \)
\(\left( \cfrac { In2 }{ k } \right) \)
none of these

Predict the rate law of the following reaction based on the data given below
\(2A+B\longrightarrow C+3D\)

Reaction number [A] (min) [B] (min) Initial rate (M s^-1)

1 0.1 0.1 x

2 0.2 0.1 2x

3 0.1 0.2 4x

4 0.2 0.2 8x

rate=k[A]²[B]
rate=k[A][B]²
rate=k[A][B]
rate=k[A]^1/2[B]^1/2

The value of rate constant of a pseudo first order reaction________________

Independent on the concentration of reactants present in small amount
Depends on the concentration of reactants present in excess
Independent of the concentration of reactants
Depends only on temperature.

For the reaction \({ N }_{ 2 }{ O }_{ 5 }\left( g \right) \longrightarrow { 2NO }_{ 2 }\left( g \right) +\cfrac { 1 }{ 2 } { O }_{ 2 }\left( g \right) \) value of rate of disappearance of N₂O₅is given as 6.5X10-² molL^-1s^-1 The rate of formation of NO₂ and O₂ is given respectively as

(3.25X10^-2 mol L^-1S^-1) and (1.3 X 10^-2 mol L^-1s^-1)
(1.3X10^-2 mol L^-1s^-1) and (3.25 X10^-2 mol L^-1s^-1)
(1.3X10^-1mol L^-1s^-1) and (3.25 X10-2 mol L^-1s^-1)
None of these

The decomposition of phosphine (PH3) on tungsten at low pressure is a first order reaction. It is because the (NEET)

rate is proportional to the surface coverage
rate is inversely proportional to the surface coverage
rate is independent of the surface coverage
rate of decomposition is slow

Part - B

Generic 2 - Answer All Question

Answer the following:
(i) Effect the adding catalyst on activation energy and Gibb's energy (ΔG).
(ii) Why do we heat the solution of oxalic acid in redox tetration against KMnO₄?

What is the study of chemical kinetics used for?
Derive integrated rate law for a zero order reaction A\(\longrightarrow \) product

For the reaction
Cl_{2 (g)} + 2NO _(g)⟶ 2NOCI_(g)
The rate law is expressed as
rate = K[Cl₂] [NO]²
What is the overall order of this reaction

Define average rate and instantaneous rate

H_2(g) + Cl_2(g) \(\overset { hv }{ \longrightarrow } \) 2HCl(g). The reaction proceeds with a uniform rate throughout. What do you conclude?

The rate law for a reaction of A, B and C has been found to be rate =k[A]²[B][L]^3/2 How would the rate of reaction change when
(i) Concentration of [L] is quadrupled
(ii) Concentration of both [A] and [B] are doubled
(iii) Concentration of [A] is halved
(iv) Concentration of [A] is reduced to \(\left( 1/3 \right) \) and concentration of [L] is quadrupled.

How does the value of rate constant vary with reactant constant.

Why does the rate of any reaction genergally decreases during the course of the reaction?

The reaction A + 2B ⟶ C obeys the rate equation. Rate = \(K{ \left[ A \right] }^{ \frac { 1 }{ 2 } }{ \left[ B \right] }^{ \frac { 3 }{ 2 } }\) What is the order of the reaction?

Define rate law and rate constant

What is an elementary reaction? Give the differences between order and molecularity of a reaction

Explain the effect of catalyst on reaction rate with an example

Describe the graphical representation of first order reaction.

The decomposition reaction of ammonia gas on platinum surface has a rate constant R = 2.5 X 10^-4mol L^-1. What is the order of the reaction.

Write the units of zeroth, first, second and third order rate constants.

A first order reaction has a specific reaction rate of 10^-3 S^-1. How much time will it take for 10gm of the reactant to reduce to 2.5 gm?

Part - C

Generic 3 - Answer All Question

Explain briefly the collision theory of bimolecular reactions

A gas phase reaction has energy of activation 200 kJ mol^-1. If the frequency factor of the reaction is is 1.6 X10¹³s^-1 Calculate the rate constant at 600 K.(e^-40.09=3.8X10^-48)

Hydrolysis of methyl acetate in aqueous solution has been studied by titrating the liberated acetic acid against sodium hydroxide. The concentration of an ester at different temperatures is given below.

t(min) 0 20 40 60 ∝

v (ml) 20.2 25.6 29.5 32.8 50.4

Show that the reaction is the first order reactions.

t(min)	0	20	40	60	∝
v (ml)	20.2	25.6	29.5	32.8	50.4

Identify the order for the following reactions
(i) Rusting of Iron
(ii) Radioactive disintegration of ₉₂U²³⁸
(iii) \(2A+3B\longrightarrow products\);rate k[A]^1/2[B]²

Write Arrhenius equation and explains the terms involved

The rate of formation of a dimer in a second order reaction is 7.5 X 10-³mol L^-1 s^-1monomer concentration. Calculate the rate constant.

For the reaction \(2x+y\longrightarrow L\)find the rate law from the following data.

[x]
(min) [y]
(min) rate
(Ms-1)

0.2 0.02 0.15

0.4 0.02 0.30

0.4 0.08 1.20

0.4 0.08 1.20

Explain pseudo first order reaction with an example
For a reaction x+y+z\(\longrightarrow \) productsthe rate law is given by ratek =k[x]^3/2[y]^1/2 what is the overall order of the reaction and what is the order of the reaction with respect to z.

The decomposition of Cl₂O₇ at 500K in the gas phase to Cl₂ and O₂ is a first order reaction. After 1 minute at 500K, the pressure of Cl₂O₇ falls from 0.08 to 0.04 atm. Calculate the rate constant in s^-1

Part - D

Generic 5 - Answer All Question

Benzene diazonium chloride in aqueous solution decomposes according to the quation \({ C }_{ 6 }{ H }_{ 5 }{ N }_{ 2 }Cl\longrightarrow { C }_{ 6 }{ H }_{ 5 }Cl+{ N }_{ 2 }\) Starting with an initial concentration of 101 g L^-1, the volume of N₂gas obtained at 50 °C at different intervals of time was found to be as under:

t(min) 6 12 18 24 30 \(\infty \)

Vol.of N₂ (ml) 19.3 32.6 41.3 46.5 50.4 58.3

Show that the above reaction follows the first order kinetics. What is the value of the rate constant?
The time for half change in a first order decomposition of a substance A is 60 seconds. Calculate the rate constant. How much of A will be left after 180 seconds?

A zero order reaction is 20% complete in 20 minutes. Calculate the value of the rate constant. In what time will the reaction be 80% complete?

The half life of the homogeneous gaseous reaction SO₂Cl₂→ SO₂ + Cl₂ which obeys first order kinetics is 8.0 minutes. How long will it take for the concentration of SO₂Cl₂ to be reduced to 1% of the initial value?

The activation energy of a reaction is 225 k Cal mol^-1and the value of rate constant at 40°C is 11.8X10^-6s^-1Calculate the frequency factor, A.

From the following data, show that the decomposition of hydrogen peroxide is a reaction of the first order:

t(min) 0 10 20

V(ml) 46.1 29.8 19.3

Where t is the time in minutes and V is the volume of standard KMnO₄ solution required for titrating the same volume of the reaction mixture.

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Reaction number	[A] (min)	[B] (min)	Initial rate (M s^-1)
1	0.1	0.1	x
2	0.2	0.1	2x
3	0.1	0.2	4x
4	0.2	0.2	8x

[x] (min)	[y] (min)	rate (Ms-1)
0.2	0.02	0.15
0.4	0.02	0.30
0.4	0.08	1.20
0.4	0.08	1.20

t(min)	6	12	18	24	30	\(\infty \)
Vol.of N₂ (ml)	19.3	32.6	41.3	46.5	50.4	58.3

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12th Chemistry Monthly Test - 1 ( Chemical Kinetics )

St. Britto Hr. Sec. School - Madurai

12th Chemistry Monthly Test - 1 ( Chemical Kinetics )-Aug 2020

Part - A

Multiple Choice Question - Answer All Question

If 75% of a first order reaction was completed in 60 minutes , 50% of the same reaction under the same conditions would be completed in

Energy of activation of a reactant is reduced by ___________

Arrhenius equation is

During a chemical reaction, the concentration of reaction

For the reaction, 2NH3 ⟶ N2 + 3H2, if \(\frac { -d[NH_{ 3 }] }{ dt } \)=k1[NH3], \(\frac { d[N_{ 2 }] }{ dt } =k_{ 2 }[NH_{ 3 }],\frac { d[{ H }_{ 2 }] }{ dt } \)=k3[NH3] then the relation between k1, k2 and k3 is

In any unimolecular reaction _______________

Activation energy is equal to _____________

After 2 hours, a radioactive substance becomes \(\left( \cfrac { 1 }{ 16 } \right) ^{ th }\) of original amount Then the half life ( in min) is

The given reaction 2 FeCl3 + SnCl2 ⟶ 2FeCl2 + SnCl4 is an example of

The time required for 50%completion of the reaction is known as ___________

Nitric oxide (NO) reacts wtih oxygen to produce nitrogen dioxide 2NO(g) + O2(g) ⟶ 2NO2(g) If the mechanism of reaction is NO + O2 \(\overset { K }{ \rightleftharpoons } \) NO3 (fast) NO3 + NO \(\overset { { K }_{ 1 } }{ \rightleftharpoons } \) NO2 + NO2 (slow)

In a first order reaction \(x\longrightarrow y\) if k is the rate constant and the initial concentration of the reactant x is 0.1M, then, the half life is

Predict the rate law of the following reaction based on the data given below \(2A+B\longrightarrow C+3D\) Reaction number [A] (min) [B] (min) Initial rate (M s-1) 1 0.1 0.1 x 2 0.2 0.1 2x 3 0.1 0.2 4x 4 0.2 0.2 8x

The value of rate constant of a pseudo first order reaction________________

For the reaction \({ N }_{ 2 }{ O }_{ 5 }\left( g \right) \longrightarrow { 2NO }_{ 2 }\left( g \right) +\cfrac { 1 }{ 2 } { O }_{ 2 }\left( g \right) \) value of rate of disappearance of N2O5is given as 6.5X10-2 molL-1s-1 The rate of formation of NO2 and O2 is given respectively as

The decomposition of phosphine (PH3) on tungsten at low pressure is a first order reaction. It is because the (NEET)

Part - B

Generic 2 - Answer All Question

Answer the following: (i) Effect the adding catalyst on activation energy and Gibb's energy (ΔG). (ii) Why do we heat the solution of oxalic acid in redox tetration against KMnO4?

What is the study of chemical kinetics used for?

Derive integrated rate law for a zero order reaction A\(\longrightarrow \) product

For the reaction Cl2 (g) + 2NO (g) ⟶ 2NOCI(g) The rate law is expressed as rate = K[Cl2] [NO]2 What is the overall order of this reaction

Define average rate and instantaneous rate

H2(g) + Cl2(g) \(\overset { hv }{ \longrightarrow } \) 2HCl(g). The reaction proceeds with a uniform rate throughout. What do you conclude?

How does the value of rate constant vary with reactant constant.

Why does the rate of any reaction genergally decreases during the course of the reaction?

The reaction A + 2B ⟶ C obeys the rate equation. Rate = \(K{ \left[ A \right] }^{ \frac { 1 }{ 2 } }{ \left[ B \right] }^{ \frac { 3 }{ 2 } }\) What is the order of the reaction?

Define rate law and rate constant

What is an elementary reaction? Give the differences between order and molecularity of a reaction

Explain the effect of catalyst on reaction rate with an example

Describe the graphical representation of first order reaction.

The decomposition reaction of ammonia gas on platinum surface has a rate constant R = 2.5 X 10-4mol L-1. What is the order of the reaction.

Write the units of zeroth, first, second and third order rate constants.

A first order reaction has a specific reaction rate of 10-3 S-1. How much time will it take for 10gm of the reactant to reduce to 2.5 gm?

Part - C

Generic 3 - Answer All Question

Explain briefly the collision theory of bimolecular reactions

A gas phase reaction has energy of activation 200 kJ mol-1. If the frequency factor of the reaction is is 1.6 X1013s-1 Calculate the rate constant at 600 K.(e-40.09=3.8X10-48)

Identify the order for the following reactions (i) Rusting of Iron (ii) Radioactive disintegration of 92U238 (iii) \(2A+3B\longrightarrow products\);rate k[A]1/2[B]2

Write Arrhenius equation and explains the terms involved

The rate of formation of a dimer in a second order reaction is 7.5 X 10-3mol L-1 s-1 monomer concentration. Calculate the rate constant.

For the reaction \(2x+y\longrightarrow L\)find the rate law from the following data. [x] (min) [y] (min) rate (Ms-1) 0.2 0.02 0.15 0.4 0.02 0.30 0.4 0.08 1.20 0.4 0.08 1.20

Explain pseudo first order reaction with an example

For a reaction x+y+z\(\longrightarrow \) productsthe rate law is given by ratek =k[x]3/2[y]1/2 what is the overall order of the reaction and what is the order of the reaction with respect to z.

The decomposition of Cl2O7 at 500K in the gas phase to Cl2 and O2 is a first order reaction. After 1 minute at 500K, the pressure of Cl2O7 falls from 0.08 to 0.04 atm. Calculate the rate constant in s-1

Part - D

Generic 5 - Answer All Question

The time for half change in a first order decomposition of a substance A is 60 seconds. Calculate the rate constant. How much of A will be left after 180 seconds?

A zero order reaction is 20% complete in 20 minutes. Calculate the value of the rate constant. In what time will the reaction be 80% complete?

The half life of the homogeneous gaseous reaction SO2Cl2 → SO2 + Cl2 which obeys first order kinetics is 8.0 minutes. How long will it take for the concentration of SO2Cl2 to be reduced to 1% of the initial value?

The activation energy of a reaction is 225 k Cal mol-1 and the value of rate constant at 40°C is 11.8X10-6s-1Calculate the frequency factor, A.

From the following data, show that the decomposition of hydrogen peroxide is a reaction of the first order: t(min) 0 10 20 V(ml) 46.1 29.8 19.3 Where t is the time in minutes and V is the volume of standard KMnO4 solution required for titrating the same volume of the reaction mixture.

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For the reaction, 2NH₃ ⟶ N₂ + 3H₂, if \(\frac { -d[NH_{ 3 }] }{ dt } \)=k₁[NH₃], \(\frac { d[N_{ 2 }] }{ dt } =k_{ 2 }[NH_{ 3 }],\frac { d[{ H }_{ 2 }] }{ dt } \)=k₃[NH₃] then the relation between k₁, k₂ and k₃ is

The given reaction
2 FeCl₃ + SnCl₂ ⟶ 2FeCl₂ + SnCl₄ is an example of

Nitric oxide (NO) reacts wtih oxygen to produce nitrogen dioxide
2NO_(g) + O_2(g) ⟶ 2NO_2(g)
If the mechanism of reaction is
NO + O₂ \(\overset { K }{ \rightleftharpoons } \) NO₃ (fast)
NO₃ + NO \(\overset { { K }_{ 1 } }{ \rightleftharpoons } \) NO₂ + NO₂ (slow)

Predict the rate law of the following reaction based on the data given below
\(2A+B\longrightarrow C+3D\)

Reaction number [A] (min) [B] (min) Initial rate (M s^-1)

1 0.1 0.1 x

2 0.2 0.1 2x

3 0.1 0.2 4x

4 0.2 0.2 8x

For the reaction \({ N }_{ 2 }{ O }_{ 5 }\left( g \right) \longrightarrow { 2NO }_{ 2 }\left( g \right) +\cfrac { 1 }{ 2 } { O }_{ 2 }\left( g \right) \) value of rate of disappearance of N₂O₅is given as 6.5X10-² molL^-1s^-1 The rate of formation of NO₂ and O₂ is given respectively as

Answer the following:
(i) Effect the adding catalyst on activation energy and Gibb's energy (ΔG).
(ii) Why do we heat the solution of oxalic acid in redox tetration against KMnO₄?

For the reaction
Cl_{2 (g)} + 2NO _(g)⟶ 2NOCI_(g)
The rate law is expressed as
rate = K[Cl₂] [NO]²
What is the overall order of this reaction

H_2(g) + Cl_2(g) \(\overset { hv }{ \longrightarrow } \) 2HCl(g). The reaction proceeds with a uniform rate throughout. What do you conclude?

The decomposition reaction of ammonia gas on platinum surface has a rate constant R = 2.5 X 10^-4mol L^-1. What is the order of the reaction.

A first order reaction has a specific reaction rate of 10^-3 S^-1. How much time will it take for 10gm of the reactant to reduce to 2.5 gm?

A gas phase reaction has energy of activation 200 kJ mol^-1. If the frequency factor of the reaction is is 1.6 X10¹³s^-1 Calculate the rate constant at 600 K.(e^-40.09=3.8X10^-48)

Identify the order for the following reactions
(i) Rusting of Iron
(ii) Radioactive disintegration of ₉₂U²³⁸
(iii) \(2A+3B\longrightarrow products\);rate k[A]^1/2[B]²

The rate of formation of a dimer in a second order reaction is 7.5 X 10-³mol L^-1 s^-1monomer concentration. Calculate the rate constant.

For the reaction \(2x+y\longrightarrow L\)find the rate law from the following data.

[x]
(min) [y]
(min) rate
(Ms-1)

0.2 0.02 0.15

0.4 0.02 0.30

0.4 0.08 1.20

0.4 0.08 1.20

For a reaction x+y+z\(\longrightarrow \) productsthe rate law is given by ratek =k[x]^3/2[y]^1/2 what is the overall order of the reaction and what is the order of the reaction with respect to z.

The decomposition of Cl₂O₇ at 500K in the gas phase to Cl₂ and O₂ is a first order reaction. After 1 minute at 500K, the pressure of Cl₂O₇ falls from 0.08 to 0.04 atm. Calculate the rate constant in s^-1

The half life of the homogeneous gaseous reaction SO₂Cl₂→ SO₂ + Cl₂ which obeys first order kinetics is 8.0 minutes. How long will it take for the concentration of SO₂Cl₂ to be reduced to 1% of the initial value?

The activation energy of a reaction is 225 k Cal mol^-1and the value of rate constant at 40°C is 11.8X10^-6s^-1Calculate the frequency factor, A.

From the following data, show that the decomposition of hydrogen peroxide is a reaction of the first order:

t(min) 0 10 20

V(ml) 46.1 29.8 19.3

Where t is the time in minutes and V is the volume of standard KMnO₄ solution required for titrating the same volume of the reaction mixture.