Theories of Chemical Reaction

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JEE Advanced 2023

LEVELJEE Advanced

The plot of $lo g k_{f}$ versus $\frac{1}{T}$ for a reversible reaction $A (g) ⇌ P (g)$ is shown. [JEE(Advanced) 2023] Pre-exponential factors for the forward and backward reactions are $1 0^{15} s^{- 1}$ and $1 0^{11} s^{- 1}$ , respectively. If the value of $lo g K$ for the reaction at $500 K$ is $6$ , the value of $∣ lo g k_{b} ∣$ at $250 K$ is ______. [ $K = equilibrium constant of the reaction$ $k_{f} = rate constant of forward reaction$ $k_{b} = rate constant of backward reaction$ ]

JEE Advanced 2016

LEVELJEE Main

According to the Arrhenius equation,

* Multiple Correct Options

(A)

A high activation energy usually implies a fast reaction

(B)

Rate constant increase with increase in temperature. This is due to a greater number of collisions whose energy exceeds the activation energy

(C)

Higher the magnitude of activation energy, stronger is the temperature dependence of the rate constant

(D)

The pre-exponential factor is a measure of the rate at which collisions occur, irrespective of their energy.

JEE Advanced 2018

LEVELJEE Advanced

Consider the following reversible reaction, $A(g) + B(g) ⇌ AB(g)$ . The activation energy of the backward reaction exceeds that of the forward reaction by $2 R T$ (in $J mol^{- 1}$ ). If the pre-exponential factor of the forward reaction is 4 times that of the reverse reaction, the absolute value of $Δ G^{θ}$ (in $J mol^{- 1}$ ) for the reaction at 300 K is____. (Given ; $ln (2) = 0.7$ , $R T = 2500 J mol^{- 1}$ at 300 K and G is the Gibbs energy)

JEE Advanced 2017

LEVELJEE Main

In a bimolecular reaction, the steric factor P was experimentally determined to be 4.5. The correct option(s) among the following is(are):

* Multiple Correct Options

(A)

The value of frequency factor predicted by Arrhenius equation is higher than that determined experimentally

(B)

The activation energy of the reaction is unaffected by the value of the steric factor

(C)

Since P = 4.5, the reaction will not proceed unless an effective catalyst is used.

(D)

Experimentally determined value of frequency factor is higher than that predicted by Arrhenius equation.

JEE Main 2020

LEVELJEE Advanced

A sample of milk splits after $60 min.$ at $300 K$ and after $40 min.$ at $400 K$ when the population of lactobacillus acidophilus in it doubles. The activation energy (in $kJ/mol$ ) for this process is closest to (Given, $R = 8.3 J mol^{- 1} K^{- 1}$ , $ln (\frac{2}{3}) = 0.4, e^{- 3} = 4.0$ )

LEVELBoard

In respect of the equation $k = A e^{- E_{a} / R T}$ in chemical kinetics, which one of the following statements is correct ?

(A)

k

is equilibrium constant

(B)

A

is adsorption factor

(C)

E_{a}

is energy of activation

(D)

R

is Rydberg constant

JEE Main 2019

LEVELJEE Main

Consider the given plots for a reaction obeying Arrhenius equation ( $0^{\circ} C < T < 30 0^{\circ} C$ ) : ( $k$ and $E_{a}$ are rate constant and activation energy, respectively)

(A)

Both I and II are wrong

(B)

Both I and II are correct

(C)

I is wrong but II is right

(D)

I is right but II is wrong

JEE Main 2019

LEVELJEE Main

If a reaction follows the Arrhenius equation, the plot $ln k$ vs $\frac{1}{R T}$ gives straight line with a gradient $(- y)$ unit. The energy required to activate the reactant is

(A)

\frac{y}{R}

unit

(B)

- y

unit

(C)

y R

unit

(D)

y

unit

LEVELJEE Main

Rate of a reaction can be expressed by Arrhenius equation as $k = A e^{- E / R T}$ . In this equation, $E$ represents

(A)

the energy above which all the colliding molecules will react

(B)

the energy below which colliding molecules will not react

(C)

the total energy of the reacting molecules at a temperature,

T

(D)

the fraction of molecules with energy greater than the activation energy of the reaction

JEE Main 2020

LEVELJEE Advanced

The rate of a reaction decreased by $3.555$ times when the temperature was changed from $4 0^{\circ} C$ to $3 0^{\circ} C$ . The activation energy (in $kJ mol^{- 1}$ ) of the reaction is ......... . (Take; $R = 8.314 J mol^{- 1} K^{- 1}$ , $ln 3.555 = 1.268$ )

JEE Main 2019

LEVELJEE Main

For a reaction, consider the plot of $ln k$ versus $1/ T$ given in the figure. If the rate constant of this reaction at $400 K$ is $1 0^{- 5} s^{- 1}$ , then the rate constant at $500 K$ is

(A)

4 \times 1 0^{- 4} s^{- 1}

(B)

1 0^{- 6} s^{- 1}

(C)

1 0^{- 4} s^{- 1}

(D)

2 \times 1 0^{- 4} s^{- 1}

JEE Main 2020

LEVELJEE Advanced

The number of molecules with energy greater than the threshold energy for a reaction increases five fold by a rise of temperature from $2 7^{\circ} C$ to $4 2^{\circ} C$ . Its energy of activation in $J/mol$ is ......... . (Take $ln 5 = 1.6094$ ; $R = 8.314 J mol^{- 1} K^{- 1}$ )

JEE Main 2021

LEVELJEE Main

If the activation energy of a reaction is $80.9 kJ mol^{- 1}$ , the fraction of molecules at $700 K$ , having enough energy to react to form products is $e^{- x}$ . The value of $x$ is ......... (Rounded off to the nearest integer) [Use, $R = 8.31 J K^{- 1} mol^{- 1}$ ].

JEE Main 2021

LEVELJEE Main

For the reaction, $a A + b B \to c C + d D$ , the plot of $lo g k$ vs $\frac{1}{T}$ is given below The temperature at which the rate constant of the reaction is $1 0^{- 4} s^{- 1}$ is ......... K (Rounded off to the nearest integer). [Given : The rate constant of the reaction is $1 0^{- 5} s^{- 1}$ at $500 K$ ]

JEE Main 2007

LEVELJEE Main

The energies of activation for forward and reverse reactions for $A_{2} + B_{2} ⇌ 2 A B$ are $180 kJ mol^{- 1}$ and $200 kJ mol^{- 1}$ , respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by $100 kJ mol^{- 1}$ . The enthalpy change of the reaction ( $A_{2} + B_{2} \to 2 A B$ ) in the presence of catalyst will be (in $kJ mol^{- 1}$ )

The rate constant of a reaction increases by five times on increase in temperature from $2 7^{\circ} C$ to $5 2^{\circ} C$ . The value of activation energy in $kJ mol^{- 1}$ is ……… (Rounded off to the nearest integer) $[R = 8.314 J K^{- 1} mol^{- 1}]$

JEE Main 2021

LEVELJEE Main

For the reaction $A \to B$ , the rate constant $k$ (in $s^{- 1}$ ) is given by $lo g_{10} k = 20.35 - \frac{( 2.47 \times 1 0 ^{3} )}{T}$ The energy of activation in $kJ mol^{- 1}$ is ......... (Nearest integer) [Given : $R = 8.314 J K^{- 1} mol^{- 1}$ ]

JEE Main 2020

LEVELJEE Main

For following reactions : $A 700 K Product$ ; $A 500 K Catalyst Product$ It was found that the $E_{a}$ is decreased by $30 kJ/mol$ in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre exponential factor is same):

(A)

198 kJ/mol

(B)

105 kJ/mol

(C)

75 kJ/mol

(D)

135 kJ/mol

JEE Main 2017

LEVELJEE Main

Two reactions $R_{1}$ and $R_{2}$ have identical preexponential factors. Activation energy of $R_{1}$ exceeds that of $R_{2}$ by $10 kJ mol^{- 1}$ . If $k_{1}$ and $k_{2}$ are rate constants for reactions $R_{1}$ and $R_{2}$ , respectively at $300 K$ , then $ln (\frac{k _{2}}{k _{1}})$ is equal to ( $R = 8.314 J mol^{- 1} K^{- 1}$ )

An exothermic reaction $X \to Y$ has an activation energy $30 kJ mol^{- 1}$ . If energy change $Δ E$ during the reaction is $- 20 kJ mol^{- 1}$ , then the activation energy for the reverse reaction in kJ is ............ .

JEE Main 2015

LEVELJEE Main

Higher order ( $> 3$ ) reactions are rare due to

(A)

low probability of simultaneous collision of all the reacting species

(B)

increase in entropy and activation energy as more molecules are involved

(C)

shifting of equilibrium towards reactants due to elastic collisions

(D)

loss of active species on collision

LEVELBoard

The rate of a chemical reaction doubles for every $1 0^{\circ} C$ rise of temperature. If the temperature is raised by $5 0^{\circ} C$ , the rate of the reaction increases by about

For the reaction of $H_{2}$ with $I_{2}$ , the rate constant is $2.5 \times 1 0^{- 4} dm^{3} mol^{- 1} s^{- 1}$ at $32 7^{\circ} C$ and $1.0 dm^{3} mol^{- 1} s^{- 1}$ at $52 7^{\circ} C$ . The activation energy for the reaction, in $kJ mol^{- 1}$ is ( $R = 8.314 J K^{- 1} mol^{- 1}$ )

The decomposition of formic acid on gold surface follows first order kinetics. If the rate constant at $300 K$ is $1.0 \times 1 0^{- 3} s^{- 1}$ and the activation energy, $E_{a} = 11.488 kJ mol^{- 1}$ , the rate constant at $200 K$ is ...... $\times 1 0^{- 5} s^{- 1}$ (Round off to the nearest integer). [Given, $R = 8.314 J mol^{- 1} K^{- 1}$ ]

JEE Main 2020

LEVELJEE Main

The rate constant ( $k$ ) of a reaction is measured at different temperature ( $T$ ), and the data are plotted in the given figure. The activation energy of the reaction in $kJ mol^{- 1}$ is ( $R$ is gas constant)

(A)

\frac{2}{R}

(B)

\frac{1}{R}

(C)

R

(D)

2 R

According to the Arrhenius equation,

In a bimolecular reaction, the steric factor P was experimentally determined to be 4.5. The correct option(s) among the following is(are):

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } In respect of the equation k=Ae−Ea​/RT in chemical kinetics, which one of the following statements is correct ?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Consider the given plots for a reaction obeying Arrhenius equation (0∘C<T<300∘C) : (k and Ea​ are rate constant and activation energy, respectively)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } If a reaction follows the Arrhenius equation, the plot lnk vs RT1​ gives straight line with a gradient (−y) unit. The energy required to activate the reactant is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Rate of a reaction can be expressed by Arrhenius equation as k=Ae−E/RT. In this equation, E represents

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } For a reaction, consider the plot of lnk versus 1/T given in the figure. If the rate constant of this reaction at 400 K is 10−5 s−1, then the rate constant at 500 K is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Higher order (>3) reactions are rare due to

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The rate of a chemical reaction doubles for every 10∘C rise of temperature. If the temperature is raised by 50∘C, the rate of the reaction increases by about

In respect of the equation $k = A e^{- E_{a} / R T}$ in chemical kinetics, which one of the following statements is correct ?

Consider the given plots for a reaction obeying Arrhenius equation ( $0^{\circ} C < T < 30 0^{\circ} C$ ) : ( $k$ and $E_{a}$ are rate constant and activation energy, respectively)

If a reaction follows the Arrhenius equation, the plot $ln k$ vs $\frac{1}{R T}$ gives straight line with a gradient $(- y)$ unit. The energy required to activate the reactant is

Rate of a reaction can be expressed by Arrhenius equation as $k = A e^{- E / R T}$ . In this equation, $E$ represents

For a reaction, consider the plot of $ln k$ versus $1/ T$ given in the figure. If the rate constant of this reaction at $400 K$ is $1 0^{- 5} s^{- 1}$ , then the rate constant at $500 K$ is

Higher order ( $> 3$ ) reactions are rare due to

The rate of a chemical reaction doubles for every $1 0^{\circ} C$ rise of temperature. If the temperature is raised by $5 0^{\circ} C$ , the rate of the reaction increases by about