For $A + B \to C + D,\;\Delta H = - 20\;{\rm{kJ}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}$ the activation energy of the forward reaction is $85\;{\rm{kJ}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}.$ The activation energy for backward reaction is …${\rm{kJ}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}$.

JEE CHEMISTRY MCQ: CHEMICAL KINETICS

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For

A + B \to C + D,\;\Delta H = - 20\;\mathrm{kJ}\;\mathrm{mo}{\mathrm{l}^{ - 1}}

the activation energy of the forward reaction is

85\;\mathrm{kJ}\;\mathrm{mo}{\mathrm{l}^{ - 1}}.

The activation energy for backward reaction is …

\mathrm{kJ}\;\mathrm{mo}{\mathrm{l}^{ - 1}}

View answer and explanation

Correct option: B

105

Option B (105) is correct because the activation energy for the backward reaction is the sum of the activation energy for the forward reaction and the absolute value of the enthalpy change.

More Questions from CHEMICAL KINETICS

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The reaction

\mathrm{A}_2+\mathrm{B}_2 \rightarrow 2 \mathrm{AB}

follows the mechanism

\begin{aligned} & {{\text{A}}_2}\mathop \rightleftharpoons \limits_{{{\text{k}}_{ - 1}}}^{{{\text{k}}_1}} {\text{A}} + {\text{A (fast) }} \\ & \mathrm{A}+\mathrm{B}_2 \xrightarrow{\mathrm{k}_2} \mathrm{AB}+\mathrm{B} \text { (slow) } \\ & \mathrm{A}+\mathrm{B} \rightarrow \mathrm{AB} \text { (fast) } \end{aligned}

The overall order of the reaction is: For the first order reaction with the rate constant

k

, which expression gives the rate half-life period?

(Initial\mathrm{ }conc.\mathrm{ } = a)

Which of the following is a zero order reaction? For a certain reaction involving a single reactant, it is found that

C_0 \sqrt{T}

is constant, where

C_0

is the initial concentration of the reactant and

T

is the half-life. What is the order of the reaction? Arrhenius equation is The energy of activation for an uncatalysed reaction is

100 \mathrm{~kJ/mol}.

Presence of a catalyst lowers the energy of activation by

75 \%

. The

\log _{10} \frac{K_2}{K_1}

of the ratio of rate constant of catalysed and uncatalysed reactions at

27^{\circ} \mathrm{C}

is?

Assume the frequency factor is same for both reactions. (Given

2.303 \times 8.314=19.147

)