JEE CHEMISTRY MCQ: CHEMICAL KINETICS

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Analyzing +4 | -1

Consider the reaction,

C{l_2}\left( {aq} \right) + {H_2}S\left( {aq} \right) \to S\left( s \right) + 2{H^ + }\left( {aq} \right) + 2C{l^ - }\left( {aq} \right)

the rate equation for this reaction is ,

rate = k\left[ {C{l_2}} \right]\left[ {{H_2}S} \right]

Which of these mechanisms is/are consistent with this rate equation?

\begin{array}{l} A.\;\;C{l_2} + {H_2}S\left( {aq} \right) \to {H^ + }C{l^ - } + C{l^ + } + H{S^ - }\left( {slow} \right)\\ \;\;\;\;\;C{l^ + } + H{S^ - } \to {H^ + }C{l^ - } + S\left( {fast} \right)\\ B.\;\;{H_2}S \leftrightarrow {H^ + } + H{S^ - }\left( {fast\;equilibrium} \right)\\ \;\;\;\;C{l_2} + H{S^ - } \to 2C{l^ - } + {H^ + }S\left( {slow} \right) \end{array}

View answer and explanation

Correct option: D

(A)Only

Option D ((A)Only) is correct because only mechanism A is consistent with the given rate equation, rate = k[Cl2][H2S], as the slow step in mechanism A directly reflects this rate law.

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

)