1
JEE Main 2025 (Online) 4th April Morning Shift
MCQ (Single Correct Answer)
+4
-1

For $\mathrm{A}_2+\mathrm{B}_2 \rightleftharpoons 2 \mathrm{AB}$

$\mathrm{E}_{\mathrm{a}}$ for forward and backward reaction are 180 and $200 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively

If catalyst lowers $\mathrm{E}_{\mathrm{a}}$ for both reaction by $100 \mathrm{~kJ} \mathrm{~mol}^{-1}$.

Which of the following statement is correct?

A
Catalyst does not alter the Gibbs energy change of a reaction.
B
The enthalpy change for the reaction is $+20 \mathrm{~kJ} \mathrm{~mol}^{-1}$.
C
Catalyst can cause non-spontaneous reactions to occur.
D
The enthalpy change for the catalysed reaction is different from that of uncatalysed reaction.
2
JEE Main 2025 (Online) 4th April Morning Shift
MCQ (Single Correct Answer)
+4
-1

Rate law for a reaction between $A$ and $B$ is given by

$$\mathrm{r}=\mathrm{k}[\mathrm{~A}]^{\mathrm{n}}[\mathrm{~B}]^{\mathrm{m}}$$

If concentration of $A$ is doubled and concentration of $B$ is halved from their initial value, the ratio of new rate of reaction to the initial rate of reaction $\left(\frac{r_2}{r_1}\right)$ is

A
$(\mathrm{n}-\mathrm{m})$
B
$2^{(\mathrm{n}-m)}$
C
$\frac{1}{2^{m+n}}$
D
$(\mathrm{m}+\mathrm{n})$
3
JEE Main 2025 (Online) 3rd April Morning Shift
MCQ (Single Correct Answer)
+4
-1

In a reaction $A+B \rightarrow C$, initial concentrations of $A$ and $B$ are related as $[A]_0=8[B]_0$. The half lives of $A$ and $B$ are 10 min and 40 min , respectively. If they start to disappear at the same time, both following first order kinetics, after how much time will the concentration of both the reactants be same?

A
20 min
B
40 min
C
80 min
D
60 min
4
JEE Main 2025 (Online) 2nd April Evening Shift
MCQ (Single Correct Answer)
+4
-1

Reactant A converts to product D through the given mechanism (with the net evolution of heat):

A → B     slow;     ΔH = +ve

B → C     fast;     ΔH = -ve

C → D     fast;     ΔH = -ve

Which of the following represents the above reaction mechanism?

A
JEE Main 2025 (Online) 2nd April Evening Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 10 English Option 1
B
JEE Main 2025 (Online) 2nd April Evening Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 10 English Option 2
C
JEE Main 2025 (Online) 2nd April Evening Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 10 English Option 3
D
JEE Main 2025 (Online) 2nd April Evening Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 10 English Option 4
JEE Main Subjects
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12