New chat PYQ Library Doubts Rank report

Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →

Chemical Kinetics and Nuclear Chemistry question

2025 · 4 Apr · Shift 2 · Q2

Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.

PYQ Library
JEE Main
Chemistry
Chemical Kinetics and Nuclear Chemistry
2025 · 4 Apr · Shift 2 · Q2

Chemical Kinetics and Nuclear Chemistry question

2025 · 4 Apr · Shift 2 · Q2

JEE MainChemistryChemical Kinetics and Nuclear ChemistryMCQ+4 / −1

Consider the following plots of

\log

of rate constant

\mathrm{k}(\log \mathrm{k})

vs

\frac{1}{\mathrm{~T}}

for three different reactions. The correct order of activation energies of these reactions is : JEE Main 2025 (Online) 4th April Evening Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 5 English

JEE Main 2025 (Online) 4th April Evening Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 5 English

A
$\mathrm{Ea}_2\gt \mathrm{Ea}_1\gt \mathrm{Ea}_3$
B
$\mathrm{Ea}_1\gt \mathrm{Ea}_3\gt \mathrm{Ea}_2$
C
$\mathrm{Ea}_3\gt \mathrm{Ea}_2\gt \mathrm{Ea}_1$
D
$\mathrm{Ea}_1\gt \mathrm{Ea}_2\gt \mathrm{Ea}_3$

View written solutionFree

Correct answer: A

For Arrhenius equation,

$k = A e^{-E_a/(RT)}$

Taking common logarithm,

$\log k = \log A - \frac{E_a}{2.303R}\cdot \frac{1}{T}$

This is the equation of a straight line in a plot of $\log k$ vs $\dfrac{1}{T}$ .

So, slope is

$m = -\frac{E_a}{2.303R}$

Hence:

slope is negative
larger the magnitude of slope, larger the activation energy $E_a$

Therefore, to compare activation energies, we compare the steepness of the three lines in the given plot.

If the three lines are labeled $1,2,3$ , then the line with the greatest negative slope has the highest $E_a$ .

From the graph, line $2$ is steepest, then line $1$ , and line $3$ is least steep.

Thus,

$|m_2| > |m_1| > |m_3|$

Therefore,

$E_{a2} > E_{a1} > E_{a3}$

Now check options:

A: $E_{a2}>E_{a1}>E_{a3}$ ✓
B: $E_{a1}>E_{a3}>E_{a2}$ ✗
C: $E_{a3}>E_{a2}>E_{a1}$ ✗
D: $E_{a1}>E_{a2}>E_{a3}$ ✗

So the correct option is A.

More from Chemical Kinetics and Nuclear Chemistry

Half life of zero order reaction $A \to$ product is 1 hour, when initial concentration of reactant is $2.0 mol L^{- 1}$ . The time required to decrease concentration of A from 0.50 to $0.25 mol L^{- 1}$ …2025 · MCQ
Reaction $A (g) \to 2 B (g) + C (g)$ is a first order reaction. It was started with pure A Which of the following option is incorrect? Includes table2025 · MCQ
A person's wound was exposed to some bacteria and then bacterial growth started to happen at the same place. The wound was later treated with some antibacterial medicine and the rate of bacterial decay(r) was found to be proportional with…2025 · MCQ
A(g) → B(g) + C(g) is a first order reaction. The reaction was started with reactant A only. Which of the following expressions is correct for rate constant k? Includes table2025 · MCQ
In a first order decomposition reaction, the time taken for the decomposition of reactant to one fourth and one eighth of its initial concentration are $t_{1}$ and $t_{2}$ (s), respectively. The ratio $t_{1} / t_{2}$ will be:2025 · MCQ
$A \to B$ The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K . If the energy barrier with respect to reactant energy for such isomeric transformation is $191.48 kJ mol^{- 1}$ …2025 · Numerical
Consider the given figure and choose the correct option : Includes diagram2025 · MCQ
For the thermal decomposition of $N_{2} O_{5} (g)$ at constant volume, the following table can be formed, for the reaction mentioned below. $2 N_{2} O_{5} (g) \to 2 N_{2} O_{4} (g) + O_{2} (g)$ … Includes table2025 · Numerical