NEET > Chemical Kinetics

Explore popular questions from Chemical Kinetics for NEET. This collection covers Chemical Kinetics previous year NEET questions hand picked by popular teachers.


Q 1.    

Correct4

Incorrect-1

Mechanism of a hypothetical reaction {tex} X _ { 2 } + Y _ { 2 } \rightarrow 2 X Y , {/tex} is given below:
(i) {tex} X _ { 2 } \rightarrow X + X {/tex} (fast)
(ii) {tex} X + Y _ { 2 } \rightleftarrows X Y + Y ( \text { slow } ) {/tex}
(iii) {tex} X + Y \rightarrow X Y {/tex} (fast)
The overall order of the reaction will be

A

2

B

0

1.5

D

1

Explanation





Q 2.    

Correct4

Incorrect-1

A first order reaction has a specific reaction rate of {tex} 10 ^ { - 2 } \mathrm { sec } ^ { -1 } {/tex} . How much time will it take for 20 g of the reactant to reduce to 5 g?

138.6{tex}\ \mathrm { sec } {/tex}

B

346.5{tex}\ \mathrm { sec } {/tex}

C

693.0{tex}\ \mathrm { sec } {/tex}

D

238.6{tex}\ \mathrm { sec } {/tex}

Explanation

Q 3.    

Correct4

Incorrect-1

The decomposition of phosphine {tex} \left( \mathrm { PH } _ { 3 } \right) {/tex} on tungsten at low pressure is a first-order reaction. It is because the

rate is proportional to the surface coverage

B

rate is inversely proportional to the surface coverage

C

rate is independent of the surface coverage

D

rate of decomposition is very slow.

Explanation

Q 4.    

Correct4

Incorrect-1

The rate of first-order reaction is 0.04 mol L{tex} ^ { - 1 }{/tex} s{tex} ^ { - 1 } {/tex} at 10 seconds and 0.03 mol L {tex} ^ { - 1 }{/tex}s{tex} ^ { - 1 } {/tex} at 20 seconds after initiation of the reaction. The half-life period of the reaction is

A

44.1{tex} \mathrm { s } {/tex}

B

54.1{tex} \mathrm { s } {/tex}

24.1 {tex} \mathrm { s } {/tex}

D

34.1 {tex} \mathrm { s } {/tex}

Explanation



Q 5.    

Correct4

Incorrect-1

The addition of a catalyst during a chemical reaction alters which of the following quantities?

A

Enthalpy

Activation energy

C

Entropy

D

Internal energy

Explanation

Q 6.    

Correct4

Incorrect-1

The rate constant of the reaction {tex} A \longrightarrow B {/tex} is {tex} 0.6 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex} . If the concentrationof {tex} A {/tex} is 5{tex}\ \mathrm { M } {/tex} , then concentration of {tex} B {/tex} after 20 minutes is

A

3.60{tex}\ \mathrm { M } {/tex}

B

0.36{tex}\ \mathrm { M } {/tex}

0.72{tex}\ \mathrm { M } {/tex}

D

1.08{tex}\ \mathrm { M } {/tex}

Explanation


Q 7.    

Correct4

Incorrect-1

The activation energy of a reaction can be determined from the slope of which of the following graphs?

{tex} \ln k \ vs. \frac { 1 } { T } {/tex}

B

{tex} \frac { T } { \ln k } vs. \frac { 1 } { T } {/tex}

C

{tex} \ln k\ vs. T {/tex}

D

{tex} \frac { \ln k } { T } vs. T {/tex}

Explanation



Q 8.    

Correct4

Incorrect-1

When initial concentration of a reactant is doubled in a reaction, its half-life period is not affected. The order of the reaction is

A

second

B

more than zero but less than first

C

Zero

first

Explanation

Q 9.    

Correct4

Incorrect-1

What is the activation energy for a reaction if its rate doubles when the temperature is raised from {tex} 20 ^ { \circ } \mathrm { C } {/tex} to {tex} 35 ^ { \circ } \mathrm { C } ? {/tex} {tex} \left( R = 8.314\ \mathrm { J\ mol } ^ { - 1 } \mathrm { K } ^ { - 1 } \right) {/tex}

34.7{tex}\ \mathrm { kJ }\ \mathrm { mol } ^ { - 1 } {/tex}

B

15.1 {tex}\ \mathrm { kJ } \ \mathrm { mol } ^ { - 1 } {/tex}

C

342{tex}\ \mathrm { kJ\ mol } ^ { - 1 } {/tex}

D

269{tex}\ \mathrm { kJ\ mol } ^ { - 1 } {/tex}

Explanation


Q 10.    

Correct4

Incorrect-1

For a reaction between {tex} A {/tex} and {tex} B {/tex} the order with respect to {tex} A {/tex} is 2 and the other with respect to {tex} B {/tex} is {tex} 3 . {/tex} The concentrations of both {tex} A {/tex} and {tex} B {/tex} are doubled, the rate will increase by a factor of

A

12

B

16

32

D

10

Explanation

Q 11.    

Correct4

Incorrect-1

A reaction is 50% complete in 2 hours and 75% complete in 4 hours. The order of reaction is

1

B

2

C

3

D

0

Explanation

Q 12.    

Correct4

Incorrect-1

In a reaction, {tex} A + B \rightarrow {/tex} product, rate is doubled when the concentration of {tex} B {/tex} is doubled, and rate increases by a factor of 8 when the concentration of both the reactants {tex} ( A \text { and } B ) {/tex} are doubled, rate law for the reaction can be written as

A

rate {tex} = k [ A ] [ B ] ^ { 2 } {/tex}

B

rate {tex} = k [ A ] ^ { 2 } [ B ] ^ { 2 } {/tex}

C

rate {tex} = k [ A ] [ B ] {/tex}

rate {tex} = k [ A ] ^ { 2 } [ B ] {/tex}

Explanation







Q 13.    

Correct4

Incorrect-1

In a zero-order reaction, for every {tex} 10 ^ { \circ } \mathrm { C } {/tex} rise of temperature, the rate is doubled. If the temperature is increased from {tex} 10 ^ { \circ } \mathrm { C } {/tex} to {tex} 100 ^ { \circ } \mathrm { C } , {/tex} the rate of the reaction will become

A

256 times

512 times

C

64 times

D

128 times

Explanation

Q 14.    

Correct4

Incorrect-1

Activation energy {tex} \left( E _ { a } \right) {/tex} and rate constants {tex} \left( k _ { 1 } \right) {/tex} and {tex} k _ { 2 } {/tex} of a chemical reaction at two different temperatures {tex} \left( T _ { 1 } \text { and } T _ { 2 } \right) {/tex} are related by

A

{tex} \ln \frac { k _ { 2 } } { k _ { 1 } } = - \frac { E _ { a } } { R } \left( \frac { 1 } { T _ { 1 } } - \frac { 1 } { T _ { 2 } } \right) {/tex}

{tex} \ln \frac { k _ { 2 } } { k _ { 1 } } = - \frac { E _ { a } } { R } \left( \frac { 1 } { T _ { 2 } } - \frac { 1 } { T _ { 1 } } \right) {/tex}

C

{tex} \ln \frac { k _ { 2 } } { k _ { 1 } } = - \frac { E _ { a } } { R } \left( \frac { 1 } { T _ { 2 } } + \frac { 1 } { T _ { 1 } } \right) {/tex}

D

{tex} \ln \frac { k _ { 2 } } { k _ { 1 } } = \frac { E _ { a } } { R } \left( \frac { 1 } { T _ { 1 } } + \frac { 1 } { T _ { 2 } } \right) {/tex}

Explanation



Q 15.    

Correct4

Incorrect-1

Which one of the following statements for the order of a reaction is incorrect?

A

Order can be determined only experimentally.

B

Order is not influenced by stoichiometric coefficient of the reactants.

C

Order of a reaction is sum of power to the concentration terms of reactants to express the rate of reaction.

Order of reaction is always whole number

Explanation

Q 16.    

Correct4

Incorrect-1

The rate of the reaction : {tex} 2 \mathrm { N } _ { 2 } \mathrm { O } _ { 5 } \rightarrow 4 \mathrm { NO } _ { 2 } + \mathrm { O } _ { 2 } {/tex} can be written in three ways.

{tex} \frac { - d \left[ \mathrm { N } _ { 2 } \mathrm { O } _ { 5 } \right] } { d t } = k \left[ \mathrm { N } _ { 2 } \mathrm { O } _ { 5 } \right] {/tex}

{tex} \frac { d \left[ \mathrm { NO } _ { 2 } \right] } { d t } = k ^ { \prime } \left[ \mathrm { N } _ { 2 } \mathrm { O } _ { 5 } \right]{/tex} ;

{tex} \frac { d \left[ \mathrm { O } _ { 2 } \right] } { d t } = k ^ { \prime \prime } \left[ \mathrm { N } _ { 2 } \mathrm { O } _ { 5 } \right] {/tex}
The relationship between {tex} k {/tex} and {tex} k ^ { \prime } {/tex} and between {tex} k {/tex} and {tex} k ^ { \prime \prime } {/tex} are

A

{tex} k ^ { \prime } = 2 k ; k ^ { \prime \prime } = k {/tex}

{tex} k ^ { \prime } = 2 k ; k ^ { \prime \prime } = k / 2 {/tex}

C

{tex} k ^ { \prime } = 2 k ; k ^ { \prime \prime } = 2 k {/tex}

D

{tex} k ^ { \prime } = k ; k ^ { \prime \prime } = k {/tex}

Explanation


Q 17.    

Correct4

Incorrect-1

The unit of rate constant for a zero order reaction is

{tex} \mathrm { mol }\ \mathrm { L } ^ { - 1 }\ \mathrm { s } ^ { - 1 } {/tex}

B

{tex} \mathrm { L }\ \mathrm { mol } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

C

{tex} \mathrm { L } ^ { 2 }\ \mathrm { mol } ^ { - 2 }\ \mathrm { s } ^ { - 1 } {/tex}

D

{tex}\mathrm s ^ { - 1 } {/tex}

Explanation

Q 18.    

Correct4

Incorrect-1

The half-life of a substance in a certain enzyme- catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L{tex} ^ { - 1 } {/tex} to 0.04 mg L {tex} ^ { - 1 } {/tex} is

A

414{tex}\ \mathrm { s } {/tex}

B

552{tex}\ \mathrm { s } {/tex}

690{tex}\ \mathrm { s }{/tex}

D

276{tex}\ \mathrm { s } {/tex}

Explanation

Q 19.    

Correct4

Incorrect-1

For the reaction {tex} \mathrm { N } _ { 2 } \mathrm { O } _ { 5 ( \mathrm { g } ) } \rightarrow 2 \mathrm { NO } _ { 2 ( \mathrm { g } ) } + 1 / 2 \mathrm { O } _ { 2 ( \mathrm { g } ) } {/tex} the value of rate of disappearance of {tex} \mathrm { N } _ { 2 } \mathrm { O } _ { 5 } {/tex} is given as {tex} 6.25 \times 10 ^ { - 3 } \mathrm { mol } \,\mathrm { L } ^ { 1 - 1 } \mathrm { s } ^ { - 1 } {/tex} . The rate of formation of {tex} \mathrm { NO } _ { 2 } {/tex} and {tex} \mathrm { O } _ { 2 } {/tex} is given respectively as

A

{tex} 6.25 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex} and
{tex} 6.25 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

{tex} 1.25 \times 10 ^ { - 2 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex} and
{tex} 3.125 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

C

{tex} 6.25 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex} and
{tex} 3.125 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

D

{tex} 1.25 \times 10 ^ { - 2 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex} and
{tex} 6.25 \times 10 ^ { - 3 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

Explanation



Q 20.    

Correct4

Incorrect-1

During the kinetic study of the reaction, {tex} 2 A + B \rightarrow C + D , {/tex} following results were obtained

Based on the above data which one of the following is correct?

A

Rate {tex} = k [ A ] ^ { 2 } [ B ] {/tex}

B

Rate {tex} = k [ A ] [ B ] {/tex}

C

Rate {tex} = k [ A ] ^ { 2 } [ B ] ^ { 2 } {/tex}

Rate {tex} = k [ A ] [ B ] ^ { 2 } {/tex}

Explanation





Q 21.    

Correct4

Incorrect-1

The rate of the reaction, {tex} 2 \mathrm { NO } + \mathrm { Cl } _ { 2 } \rightarrow 2 \mathrm { NOCl } {/tex} is given by the rate equation rate {tex} = k [ \mathrm { NO } ] ^ { 2 } \left[ \mathrm { Cl } _ { 2 } \right] . {/tex} The value of the rate constant can be increased by

increasing the temperature

B

increasing the concentration of NO

C

increasing the concentration of the {tex} \mathrm { Cl } _ { 2 } {/tex}

D

doing all of these.

Explanation

Q 22.    

Correct4

Incorrect-1

For the reaction, {tex} \mathrm { N } _ { 2 } + 3 \mathrm { H } _ { 2 } \rightarrow 2 \mathrm { NH } _ { 3 } , {/tex} if

{tex} \frac { d \left[ \mathrm { NH } _ { 3 } \right] } { d t } = 2 \times 10 ^ { - 4 } \mathrm { mol } \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } , {/tex}

the value of

{tex} \frac { - d \left[ \mathrm { H } _ { 2 } \right] } { d t } {/tex} would be

A

{tex} 4 \times 10 ^ { - 4 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

B

{tex} 6 \times 10 ^ { - 4 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

C

{tex} 1 \times 10 ^ { - 4 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

{tex} 3 \times 10 ^ { - 4 } \mathrm { mol }\ \mathrm { L } ^ { - 1 } \mathrm { s } ^ { - 1 } {/tex}

Explanation


Q 23.    

Correct4

Incorrect-1

In the reaction,
{tex} \ \mathrm{ Br O } _ {3 ( a q ) } ^ { - } + 5 \mathrm { Br } _ { ( a q ) } ^ { - } + 6 \mathrm { H } ^ { + } \rightarrow 3 \mathrm { Br } _ { 2 ( \ell ) } + 3 \mathrm { H } _ { 2 } \mathrm { O } _ { ( l ) } {/tex}
The rate of appearance of bromine {tex}\mathrm{(Br_{2} )}{/tex} is related to rate of disappearance of bromide ions as

A

{tex} \frac { d \left[ \mathrm { Br } _ { 2 } \right] } { d t } = - \frac { 5 } { 3 } \frac { d \left[ \mathrm { Br } ^ { - } \right] } { d t } {/tex}

B

{tex} \frac { d \left[ \mathrm { Br } _ { 2 } \right] } { d t } = \frac { 5 } { 3 } \frac { d \left[ \mathrm { Br } ^ { - } \right] } { d t } {/tex}

C

{tex} \frac { d \left[ \mathrm { Br } _ { 2 } \right] } { d t } = \frac { 3 } { 5 } \frac { d \left[ \mathrm { Br } ^ { - } \right] } { d t } {/tex}

{tex} \frac { d \left[ \mathrm { Br } _ { 2 } \right] } { d t } = - \frac { 3 } { 5 } \frac { d \left[ \mathrm { Br } ^ { - } \right] } { d t } {/tex}

Explanation


Q 24.    

Correct4

Incorrect-1

Half-life period of a first order reaction is 1386 seconds. The specific rate constant of the reaction is

A

{tex} 0.5 \times 10 ^ { - 2 } \mathrm { s } ^ { - 1 } {/tex}

{tex} 0.5 \times 10 ^ { - 3 } \mathrm { s } ^ { - 1 } {/tex}

C

{tex} 5.0 \times 10 ^ { - 2 } \mathrm { s } ^ { - 1 } {/tex}

D

{tex} 5.0 \times 10 ^ { - 3 } \mathrm { s } ^ { - 1 } {/tex}

Explanation

Q 25.    

Correct4

Incorrect-1

For the reaction {tex} A + B \rightarrow {/tex} products, it is observed that
(1) on doubling the initial concentration of {tex} A {/tex} only, the rate of reaction is also doubled and
(ii) on doubling the initial concentration of
both {tex} A {/tex} and {tex} B , {/tex} there is a change by a factor of 8 in the rate of the reaction. The rate of this reaction is given by

rate {tex} = k [ A ] [ B ] ^ { 2 } {/tex}

B

rate {tex} = k [ A ] _ { 2 } ^ { 2 } [ B ] ^ { 2 } {/tex}

C

rate {tex} = k [ A ] [ B ] {/tex}

D

rate {tex} = k [ A ] ^ { 2 } [ B ] {/tex}

Explanation