COMEDK 2025 Evening Shift | Chemical Kinetics Question 1 | Chemistry

When the temperature of a reaction $\mathrm{A}+\mathrm{B} \rightarrow \mathrm{C}$ is increased from 300 K to 310 K the rate constant increases by $12 \%$. What is the Activation energy of the reaction?

$163.9 \mathrm{~kJ} / \mathrm{mol}$

$85.69 \mathrm{~kJ} / \mathrm{mol}$

$192.17 \mathrm{~kJ} / \mathrm{mol}$

$8.76 \mathrm{~kJ} / \mathrm{mol}$

COMEDK 2025 Evening Shift

MCQ (Single Correct Answer)

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The order of a reaction $\mathrm{W}+\mathrm{X} ---- \rightarrow \mathrm{Y}+\mathrm{Z}$ with respect to W is 3 and with respect to X is 1. If the concentrations of both W and X are tripled, the rate of reaction will increase by _________ times.

COMEDK 2025 Evening Shift

MCQ (Single Correct Answer)

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The decomposition of $\mathrm{PH}_3$ follows first order kinetics. The time required for $3 / 4^{\text {th }}$ of $\mathrm{PH}_3$ to decompose is 75.76 s . Calculate the fraction of original amount of $\mathrm{PH}_3$ which will remain after 2.0 minutes.

0.354

0.111

0.954

0.898

COMEDK 2025 Evening Shift

MCQ (Single Correct Answer)

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Choose the correct statement.

The plot of $[A]$ versus time " $t$ " for a zero order reaction is a horizontal line parallel to the $x$-axis which represents " $t$ "

For a first order reaction the time taken for $3 / 4^{\text {th }}$ completion is 2 times the half-life period.

For a second order reaction the rate of reaction with respect to reactant becomes 27 times when its concentration is tripled.

Molecularity of a chemical reaction is always greater than order of the reaction.

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