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JEE MAIN - Chemistry (2025 - 23rd January Morning Shift)

1

Given below are two statements:

Statement I: In Lassaigne's test, the covalent organic molecules are transformed into ionic compounds.

Statement II: The sodium fusion extract of an organic compound having N and S gives prussian blue colour with $\mathrm{FeSO}_4$ and $\mathrm{Na}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$

In the light of the above statements, choose the correct answer from the options given below

Answer
(D)
Statement I is true but Statement II is false
2

Match the List - I with List - II

List - I
(Classification of molecules based on octet rule)		 List - II
(Example)
(A) Molecules obeying octet rule (I) $\mathrm{NO}, \mathrm{NO}_2$
(B) Molecules with incomplete octet (II) $\mathrm{BCl}_3, \mathrm{AlCl}_3$
(C) Molecules with incomplete octet with odd electron (III) $\mathrm{H}_2 \mathrm{SO}_4, \mathrm{PCl}_5$
(D) Molecules with expanded octet (IV) $\mathrm{CCl}_4, \mathrm{CO}_2$

Choose the correct answer from the options given below:

Answer
(C)
A-IV, B-II, C-I, D-III
3
What amount of bromine will be required to convert 2 g of phenol into 2,4,6-tribromophenol?

(Given molar mass in $\mathrm{g} \mathrm{mol}^{-1}$ of $\mathrm{C}, \mathrm{H}, \mathrm{O}, \mathrm{Br}$ are $12,1,16,80$ respectively )
Answer
(B)
10.22 g
4
The correct set of ions (aqueous solution) with same colour from the following is:
Answer
(A)
$\mathrm{V}^{2+}, \mathrm{Cr}^{3+}, \mathrm{Mn}^{3+}$
5
$$ \mathrm{FeO}_4^{2-} \xrightarrow{+2.0 \mathrm{~V}} \mathrm{Fe}^{3+} \xrightarrow{0.8 \mathrm{~V}} \mathrm{Fe}^{2+} \xrightarrow{-0.5 \mathrm{~V}} \mathrm{Fe}^0 $$

In the above diagram, the standard electrode potentials are given in volts (over the arrow).

The value of $\mathrm{E}_{\mathrm{FeO}_4^{2-} / \mathrm{Fe}^{2+}}$ is :
Answer
(D)
1.7 V
6
$\mathrm{CrCl}_3 \cdot \mathrm{xNH}_3$ can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of $0.558^{\circ} \mathrm{C}$. Assuming $100 \%$ ionisation of this complex and coordination number of Cr is 6 , the complex will be (Given $\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ )
Answer
(A)
$\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2$
7
The major product of the following reaction is: $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}=\mathrm{O} \xrightarrow[\text { reflux }]{\substack{\text { excess } \mathrm{HCHO} \\ \text { alkali }}}$ ?
Answer
(C)
JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 9 English Option 3
8
Propane molecule on chlorination under photochemical condition gives two di-chloro products, " $x$ " and " $y$ ". Amongst " $x$ " and " $y$ ", " $x$ " is an optically active molecule. How many tri-chloro products (consider only structural isomers) will be obtained from " x " when it is further treated with chlorine under the photochemical condition?
Answer
(C)
3
9
The incorrect statement among the following is
Answer
(B)
$\mathrm{SO}_2$ can act as an oxidizing agent, but not as a reducing agent.
10

The correct stability order of the following species/molecules is :

JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Basics of Organic Chemistry Question 7 English

Answer
(A)
$\mathrm{q>r>p}$
11
$2.8 \times 10^{-3} \mathrm{~mol}$ of $\mathrm{CO}_2$ is left after removing $10^{21}$ molecules from its ' $x$ ' mg sample. The mass of $\mathrm{CO}_2$ taken initially is Given: $\mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{~mol}^{-1}$
Answer
(B)
196.2 mg
12

Given below are two statements:

Statement I: Fructose does not contain an aldehydic group but still reduces Tollen's reagent

Statement II: In the presence of base, fructose undergoes rearrangement to give glucose.

In the light of the above statements, choose the correct answer from the options given below

Answer
(C)
Both Statement I and Statement II are true
13

Which of the following happens when $\mathrm{NH}_4 \mathrm{OH}$ is added gradually to the solution containing 1 M $\mathrm{A}^{2+}$ and $1 \mathrm{M} \mathrm{B}^{3+}$ ions?

Given : $\mathrm{K}_{\text {sp }}\left[\mathrm{A}(\mathrm{OH})_2\right]=9 \times 10^{-10}$ and $\mathrm{K}_{\mathrm{sp}}\left[\mathrm{B}(\mathrm{OH})_3\right]=27 \times 10^{-18}$ at 298 K.

Answer
(D)
$\mathrm{B}(\mathrm{OH})_3$ will precipitate before $\mathrm{A}(\mathrm{OH})_2$
14
Ice at $-5^{\circ} \mathrm{C}$ is heated to become vapor with temperature of $110^{\circ} \mathrm{C}$ at atmospheric pressure. The entropy change associated with this process can be obtained from
Answer
(D)
$\int_{268 \mathrm{~K}}^{273 \mathrm{~K}} \frac{\mathrm{C}_{\mathrm{p}, \mathrm{m}}}{\mathrm{T}} \mathrm{dT}+\frac{\Delta \mathrm{H}_{\mathrm{m}}, \text { fusion }}{\mathrm{T}_{\mathrm{f}}}+\frac{\Delta \mathrm{H}_{\mathrm{m}, \text { vaporisation }}^{373 \mathrm{~K}}}{\mathrm{~T}_{\mathrm{b}}}+\int_{273 \mathrm{~K}} \frac{\mathrm{C}_{\mathrm{p}, \mathrm{m}} \mathrm{dT}}{T}+\int_{373 \mathrm{~K}}^{383 \mathrm{~K}} \frac{\mathrm{C}_{\mathrm{p}, \mathrm{m}} \mathrm{dT}}{\mathrm{T}}$
15

Match the List - I with List - II

List - I
Name reaction		 List - II
Product obtainable
(A) Swarts reaction (I) Ethyl benzene
(B) Sandmeyer's reaction (II) Ethyl iodide
(C) Wurtz Fittig reaction (III) Cyanobenzene
(D) Finkelstein reaction (IV) Ethyl fluoride

Choose the correct answer from the options given below:

Answer
(D)
A-IV, B-III, C-I, D-II
16
The element that does not belong to the same period of the remaining elements (modern periodic table) is:
Answer
(D)
Palladium
17
The d-electronic configuration of an octahedral Co (II) complex having magnetic moment of 3.95 BM is:
Answer
(C)
$\mathrm{t}_{2 \mathrm{~g}}{ }^5 \mathrm{e}_{\mathrm{g}}{ }^2$
18
The complex that shows Facial - Meridional isomerism is :
Answer
(B)
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]$
19

Heat treatment of muscular pain involves radiation of wavelength of about 900 nm . Which spectral line of H atom is suitable for this?

Given : Rydberg constant $\left.\mathrm{R}_{\mathrm{H}}=10^5 \mathrm{~cm}^{-1}, \mathrm{~h}=6.6 \times 10^{-34} \mathrm{~J} \mathrm{~s}, \mathrm{c}=3 \times 10^8 \mathrm{~m} / \mathrm{s}\right)$

Answer
(D)
Paschen series, $\infty \rightarrow 3$
20

Which among the following react with Hinsberg's reagent?

A. JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 4 English 1

B. JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 4 English 2

$\text { C. } \mathrm{CH}_3-\mathrm{NH}_2$

D. $\mathrm{N}\left(\mathrm{CH}_3\right)_3$

E. JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 4 English 3

Choose the correct answer from the options given below :

Answer
(A)
A, C and E only
21

For the thermal decomposition of $\mathrm{N}_2 \mathrm{O}_5(\mathrm{~g})$ at constant volume, the following table can be formed, for the reaction mentioned below.

$$2 \mathrm{~N}_2 \mathrm{O}_5(\mathrm{~g}) \rightarrow 2 \mathrm{~N}_2 \mathrm{O}_4(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g})$$

Sr. No. Time/s Total pressure/(atm)
1 0 0.6
2 100 '$\mathrm{x}$'

$\mathrm{x}=$ __________ $\times 10^{-3} \mathrm{~atm}$ [nearest integer]

Given : Rate constant for the reaction is $4.606 \times 10^{-2} \mathrm{~s}^{-1}$.

Answer
897
22
The standard enthalpy and standard entropy of decomposition of $\mathrm{N}_2 \mathrm{O}_4$ to $\mathrm{NO}_2$ are $55.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $175.0 \mathrm{~J} / \mathrm{K} / \mathrm{mol}$ respectively. The standard free energy change for this reaction at $25^{\circ} \mathrm{C}$ in J $\mathrm{mol}^{-1}$ is ________ (Nearest integer)
Answer
2850
23

If 1 mM solution of ethylamine produces $\mathrm{pH}=9$, then the ionization constant $\left(\mathrm{K}_{\mathrm{b}}\right)$ of ethylamine is $10^{-x}$. The value of $x$ is _________ (nearest integer).

[The degree of ionization of ethylamine can be neglected with respect to unity.]

Answer
7
24

Consider the following sequence of reactions to produce major product (A)

JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 5 English

$\begin{aligned} & \text { Molar mass of product }(\mathrm{A}) \text { is } \mathrm{g} \mathrm{~mol}^{-1} \text {. } \\ & \text { (Given molar mass in } \mathrm{g} \mathrm{~mol}^{-1} \text { of } \mathrm{C}: 12, \mathrm{H}: 1, \mathrm{O}: 16, \mathrm{Br}: 80, \mathrm{~N}: 14, \mathrm{P}: 31 \text { ) }\end{aligned}$

Answer
171
25

During " S " estimation, 160 mg of an organic compound gives 466 mg of barium sulphate. The percentage of Sulphur in the given compound is _________ %.

(Given molar mass in $\mathrm{g} \mathrm{~mol}^{-1}$ of $\mathrm{Ba}: 137, \mathrm{~S}: 32, {\mathrm{O}: 16}$)

Answer
40