JEE MAIN - Chemistry (2025 - 24th January Morning Shift)

1
For a reaction, $\mathrm{N}_2 \mathrm{O}_{5(\mathrm{~g})} \rightarrow 2 \mathrm{NO}_{2(\mathrm{~g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}$ in a constant volume container, no products were present initially. The final pressure of the system when $50 \%$ of reaction gets completed is
Answer
(C)
$7 / 4$ times of initial pressure
2
The large difference between the melting and boiling points of oxygen and sulphur may be explained on the basis of
Answer
(A)
Atomicity
3

Given below are two statements I and II.

Statement I : Dumas method is used for estimation of "Nitrogen" in an organic compound.

Statement II : Dumas method involves the formation of ammonium sulphate by heating the organic compound with conc $\mathrm{H}_2 \mathrm{SO}_4$.

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

Answer
(A)
Statement I is true but Statement II is false
4
Consider the given plots of vapour pressure (VP) vs temperature(T/K). Which amongst the following options is correct graphical representation showing $\Delta \mathrm{T}_{\mathrm{f}}$, depression in the freezing point of a solvent in a solution?
Answer
(C)
JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Solutions Question 2 English Option 3
5

Given below are two statements:

Statement I: The conversion proceeds well in the less polar medium.

$$\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{Cl} \xrightarrow{\mathrm{HO}^{-}} \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{OH}+\mathrm{Cl}^{(-)}$$

Statement II: The conversion proceeds well in the more polar medium.

JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Haloalkanes and Haloarenes Question 4 English

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

Answer
(D)
Both Statement I and Statement II are true
6
Preparation of potassium permanganate from $\mathrm{MnO}_2$ involves two step process in which the 1st step is a reaction with KOH and $\mathrm{KNO}_3$ to produce
Answer
(C)
$\mathrm{K}_2 \mathrm{MnO}_4$
7
Which one of the carbocations from the following is most stable?
Answer
(C)
JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Basics of Organic Chemistry Question 6 English Option 3
8

The product $(\mathrm{A})$ formed in the following reaction sequence is

JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Hydrocarbons Question 1 English

Answer
(C)
JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Hydrocarbons Question 1 English Option 3
9
$\mathrm{K}_{\mathrm{sp}}$ for $\mathrm{Cr}(\mathrm{OH})_3$ is $1.6 \times 10^{-30}$. What is the molar solubility of this salt in water?
Answer
(C)
$\sqrt[4]{\frac{1.6 \times 10^{-30}}{27}}$
10

Which of the following linear combination of atomic orbitals will lead to formation of molecular orbitals in homonuclear diatomic molecules [internuclear axis in $z$-direction] ?

A. $2 \mathrm{p}_{\mathrm{z}}$ and $2 \mathrm{p}_{\mathrm{x}}$

B. 2 s and $2 \mathrm{p}_{\mathrm{x}}$

C. $3 d_{x y}$ and $3 d_{x^2-y^2}$

D. 2 s and $2 \mathrm{p}_{\mathrm{z}}$

E. $2 p_z$ and $3 d_{x^2-y^2}$

Choose the correct answer from the options given below:

Answer
(A)
D Only
11

Which of the following statements are NOT true about the periodic table?

A. The properties of elements are function of atomic weights.

B. The properties of elements are function of atomic numbers.

C. Elements having similar outer electronic configurations are arranged in same period.

D. An element's location reflects the quantum numbers of the last filled orbital.

E. The number of elements in a period is same as the number of atomic orbitals available in energy level that is being filled.

Choose the correct answer from the options given below:

Answer
(A)
A, C and E Only
12
One mole of the octahedral complex compound $\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}_3$ gives 3 moles of ions on dissolution in water. One mole of the same complex reacts with excess of $\mathrm{AgNO}_3$ solution to yield two moles of $\mathrm{AgCl}_{(\mathrm{s})}$. The structure of the complex is:
Answer
(A)
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2$
13

Which of the following statement is true with respect to $\mathrm{H}_2 \mathrm{O}, \mathrm{NH}_3$ and $\mathrm{CH}_4$ ?

A. The central atoms of all the molecules are $\mathrm{sp}^3$ hybridized.

B. The $\mathrm{H}-\mathrm{O}-\mathrm{H}, \mathrm{H}-\mathrm{N}-\mathrm{H}$ and $\mathrm{H}-\mathrm{C}-\mathrm{H}$ angles in the above molecules are $104.5^{\circ}, 107.5^{\circ}$ and $109.5^{\circ}$, respectively.

C. The increasing order of dipole moment is $\mathrm{CH}_4<\mathrm{NH}_3<\mathrm{H}_2 \mathrm{O}$.

D. Both $\mathrm{H}_2 \mathrm{O}$ and $\mathrm{NH}_3$ are Lewis acids and $\mathrm{CH}_4$ is a Lewis base.

E. A solution of $\mathrm{NH}_3$ in $\mathrm{H}_2 \mathrm{O}$ is basic. In this solution $\mathrm{NH}_3$ and $\mathrm{H}_2 \mathrm{O}$ act as Lowry-Bronsted acid and base respectively.

Choose the correct answer from the options given below:

Answer
(C)
A, B and C Only
14
Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.
Answer
(D)
Both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ are (+ve)
15
Which of the following arrangements with respect to their reactivity in nucleophilic addition reaction is correct?
Answer
(B)
acetophenone $<$ p-tolualdehyde $<$ benzaldehyde $<$ p- nitrobenzaldehyde
16

The carbohydrate "Ribose" present in DNA, is

A. A pentose sugar

B. present in pyranose from

C. in "D" configuration

D. a reducing sugar, when free

E. in $\propto$-anomeric form

Choose the correct answer from the options given below:

Answer
(C)
A, C and D Only
17
Aman has been asked to synthesise the molecule JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 5 English He thought of preparing the molecule using an aldol condensation reaction. He found a few cyclic alkenes in his laboratory. He thought of performing ozonolysis reaction on alkene to produce a dicarbonyl compound followed by aldol reaction to prepare " $x$ ". Predict the suitable alkene that can lead to the formation of " $x$ ".
Answer
(D)
JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 5 English Option 4
18

For the given cell

$$\mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{Ag}_{(\mathrm{aq})}^{+} \rightarrow \mathrm{Fe}^{3+}(\mathrm{aq})+\mathrm{Ag}_{(\mathrm{s})}$$

The standard cell potential of the above reaction is Given:

$$\begin{array}{lr} \mathrm{Ag}^{+}+\mathrm{e}^{-} \rightarrow \mathrm{Ag} & \mathrm{E}^\theta=\mathrm{xV} \\ \mathrm{Fe}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Fe} & \mathrm{E}^\theta=\mathrm{yV} \\ \mathrm{Fe}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Fe} & \mathrm{E}^\theta=\mathrm{zV} \end{array}$$

Answer
(A)
$x+2 y-3 z$
19

Following are the four molecules "P", "Q", "R" and "S".

Which one among the four molecules will react with $\mathrm{H}-\mathrm{Br}_{(\mathrm{aq})}$ at the fastest rate?

JEE Main 2025 (Online) 24th January Morning Shift Chemistry - Haloalkanes and Haloarenes Question 5 English

Answer
(A)
Q
20
Which of the following ions is the strongest oxidizing agent? (Atomic Number of $\mathrm{Ce}=58, \mathrm{Eu}=63, \mathrm{~Tb}=65, \mathrm{Lu}=71$)
Answer
(C)
$\mathrm{Tb}^{4+}$
21

$37.8 \mathrm{~g} \mathrm{~N}_2 \mathrm{O}_5$ was taken in a 1 L reaction vessel and allowed to undergo the following reaction at 500 K

$$2 \mathrm{~N}_2 \mathrm{O}_{5(\mathrm{~g})} \rightleftharpoons 2 \mathrm{~N}_2 \mathrm{O}_{4(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})}$$

The total pressure at equilibrium was found to be 18.65 bar.

Then, $\mathrm{Kp}=$ _________ $\times 10^{-2}$ [nearest integer]

Assume $\mathrm{N}_2 \mathrm{O}_5$ to behave ideally under these conditions.

Given: $\mathrm{R}=0.082$ bar $\mathrm{L} \mathrm{mol}^{-1} \mathrm{~K}^{-1}$

Answer
962
22

Among the following cations, the number of cations which will give characteristic precipitate in their identification tests with $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ is ________.

$$\mathrm{Cu}^{2+}, \mathrm{Fe}^{3+}, \mathrm{Ba}^{2+}, \mathrm{Ca}^{2+}, \mathrm{NH}_4^{+}, \mathrm{Mg}^{2+}, \mathrm{Zn}^{2+}$$

Answer
3
23

Consider the following reaction occurring in the blast furnace:

$$\mathrm{Fe}_3 \mathrm{O}_{4(\mathrm{~s})}+4 \mathrm{CO}_{(\mathrm{g})} \rightarrow 3 \mathrm{Fe}_{(\mathrm{l})}+4 \mathrm{CO}_{2(\mathrm{~g})}$$

' $x$ ' kg of iron is produced when $2.32 \times 10^3 \mathrm{~kg} \mathrm{Fe}_3 \mathrm{O}_4$ and $2.8 \times 10^2 \mathrm{~kg} \mathrm{CO}$ are brought together in the furnace. The value of ' $x$ ' is _________ . (nearest integer)

{Given: molar mass of $\mathrm{Fe}_3 \mathrm{O}_4=232 \mathrm{~g} \mathrm{~mol}^{-1}$

molar mass of $\mathrm{CO}=28 \mathrm{~g} \mathrm{~mol}^{-1}$

molar mass of $\mathrm{Fe}=56 \mathrm{~g} \mathrm{~mol}^{-1}$}

Answer
420
24

Xg of benzoic acid on reaction with aq $\mathrm{NaHCO}_3$ released $\mathrm{CO}_2$ that occupied 11.2 L volume at STP.

X is _________ g.

Answer
61
25

Standard entropies of $\mathrm{X}_2, \mathrm{Y}_2$ and $\mathrm{XY}_5$ are 70, 50 and $110 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ respectively. The temperature in Kelvin at which the reaction

$$\frac{1}{2} \mathrm{X}_2+\frac{5}{2} \mathrm{Y}_2 \rightleftharpoons \mathrm{XY}_5 \Delta \mathrm{H}^{\ominus}=-35 \mathrm{~kJ} \mathrm{~mol}^{-1}$$

will be at equilibrium is __________ (Nearest integer)

Answer
700