1
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1

The reaction $A_2 + B_2 \rightarrow 2AB$ follows the mechanism

$\begin{aligned} & A_2 \xlongequal[k_{-1}]{k_1} A+A \text { (fast) } \\\\ & A+B_2 \xrightarrow{k_2} A B+B \text { (slow) } \\\\ & A+B \rightarrow A B \text { (fast) }\end{aligned}$

The overall order of the reaction is :

A

3

B

2.5

C

1.5

D

2

2
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1

If $a$0 is denoted as the Bohr radius of hydrogen atom, then what is the de-Broglie wavelength (λ) of the electron present in the second orbit of hydrogen atom? [n : any integer]

A

$\frac{8 \pi a_0}{n}$

B

$\frac{2 a_0}{n \pi}$

C

$\frac{n a_0}{4 \pi}$

D

$\frac{4 \pi a_0}{n}$

3
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1

The standard reduction potential values of some of the p-block ions are given below. Predict the one with the strongest oxidising capacity.

A

$E^o_{\text{Sn}^{4+}/\text{Sn}^{2+}} = +1.15 \text{ V}$

B

$E^o_{\text{Al}^{3+}/\text{Al}} = -1.66 \text{ V}$

C

$E^o_{\text{Pb}^{4+}/\text{Pb}^{2+}} = +1.67 \text{ V}$

D

$E^o_{\text{Tl}^{3+}/\text{Tl}} = +1.26 \text{ V}$

4
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1

Choose the correct statements.

(A) Weight of a substance is the amount of matter present in it.

(B) Mass is the force exerted by gravity on an object.

(C) Volume is the amount of space occupied by a substance.

(D) Temperatures below 0°C are possible in Celsius scale, but in Kelvin scale negative temperature is not possible.

(E) Precision refers to the closeness of various measurements for the same quantity.

Choose the correct answer from the options given below :

A

(B), (C) and (D) Only

B

(A), (B) and (C) Only

C

(C), (D) and (E) Only

D

(A), (D) and (E) Only

JEE Main Papers
2023
2021
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