1
JEE Main 2026 (Online) 21st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Decomposition of A is a first order reaction at T(K) and is given by  A(g) → B(g) + C(g).

In a closed 1 L vessel, 1 bar A(g) is allowed to decompose at T(K). After 100 minutes, the total pressure was 1.5 bar. What is the rate constant (in min−1) of the reaction? (log 2 = 0.3)

A

$6.9 × 10^{-4}$

B

$6.9 × 10^{-3}$

C

$6.9 × 10^{-1}$

D

$6.9 × 10^{-2}$

2
JEE Main 2025 (Online) 8th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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:

A

$\frac{4}{3}$

B

$\frac{3}{2}$

C

$\frac{3}{4}$

D

$\frac{2}{3}$

3
JEE Main 2025 (Online) 7th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A(g) → B(g) + C(g) is a first order reaction.

Time t
Psystem Pt P

The reaction was started with reactant A only. Which of the following expressions is correct for rate constant k?

A
$\mathrm{k}=\frac{1}{\mathrm{t}} \ln \frac{\mathrm{p}_{\infty}}{\mathrm{p}_{\mathrm{t}}}$
B
$\mathrm{k}=\frac{1}{\mathrm{t}} \ln \frac{\mathrm{p}_{\infty}}{2\left(\mathrm{p}_{\infty}-\mathrm{p}_{\mathrm{t}}\right)}$
C
$\mathrm{k}=\frac{1}{\mathrm{t}} \ln \frac{2\left(\mathrm{p}_{\infty}-\mathrm{p}_{\mathrm{t}}\right)}{\mathrm{p}_{\mathrm{t}}}$
D
$\mathrm{k}=\frac{1}{\mathrm{t}} \ln \frac{\mathrm{p}_{\infty}}{\left(\mathrm{p}_{\infty}-\mathrm{p}_{\mathrm{t}}\right)}$
4
JEE Main 2025 (Online) 7th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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 the square of the existing number of bacteria at any instance. Which of the following set of graphs correctly represents the 'before' and 'after' situation of the application of the medicine?

[Given: $N=$ No. of bacteria, $t=$ time, bacterial growth follows $1^{\text {st }}$ order kinetics.]

A
JEE Main 2025 (Online) 7th April Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 36 English Option 1
B
JEE Main 2025 (Online) 7th April Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 36 English Option 2
C
JEE Main 2025 (Online) 7th April Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 36 English Option 3
D
JEE Main 2025 (Online) 7th April Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 36 English Option 4

JEE Main Subjects

Browse all chapters by subject