JEE MAIN - Chemistry (2025 - 22nd January Morning Shift)

1
Which of the following electrolyte can be used to obtain $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8$ by the process of electrolysis ?
Answer
(A)
Concentrated solution of sulphuric acid
2
Which of the following statement is not true for radioactive decay?
Answer
(B)
Decay constant increases with increase in temperature.
3

Given below are two statements :

Statement I : $\quad \mathrm{CH}_3-\mathrm{O}-\mathrm{CH}_2-\mathrm{Cl}$ will undergo $\mathrm{S}_{\mathrm{N}} 1$ reaction though it is a primary halide.

Statement II : JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Haloalkanes and Haloarenes Question 10 English will not undergo $\mathrm{S}_{\mathrm{N}} 2$ reaction very easily though it is a primary halide.

In the light of the above statements, choose the most appropriate answer from the options given below :

Answer
(B)
Both Statement I and Statement II are correct
4

The products formed in the following reaction sequence are :

JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 9 English

Answer
(D)
JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 9 English Option 4
5
From the magnetic behaviour of $\left[\mathrm{NiCl}_4\right]^{2-}$ (paramagnetic) and $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ (diamagnetic), choose the correct geometry and oxidation state.
Answer
(B)
$\left[\mathrm{NiCl}_4\right]^{2-}: \mathrm{Ni}^{\mathrm{II}}$, tetrahedral $\left[\mathrm{Ni}(\mathrm{CO})_4\right]: \mathrm{Ni}(0)$, tetrahedral
6

The compounds which give positive Fehling's test are :

JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 12 English

Choose the correct answer from the options given below :

Answer
(D)
(C), (D) and (E) Only
7

Match List-I with List-II.

List - I List - II
(A) $\mathrm{Al}^{3+}<\mathrm{Mg}^{2+}<\mathrm{Na}^{+}<\mathrm{F}^{-}$ (I) Ionisation Enthalpy
(B) $\mathrm{B}<\mathrm{C}<\mathrm{O}<\mathrm{N}$ (II) Metallic character
(C) $\mathrm{B}<\mathrm{Al}<\mathrm{Mg}<\mathrm{K}$ (III) Electronegativity
(D) $\mathrm{Si}<\mathrm{P}<\mathrm{S}<\mathrm{Cl}$ (IV) Ionic radii

Choose the correct answer from the options given below :

Answer
(A)
(A)-(IV), (B)-(I), (C)- (II), (D)-(III)
8
A vessel at 1000 K contains $\mathrm{CO}_2$ with a pressure of 0.5 atm . Some of $\mathrm{CO}_2$ is converted into CO on addition of graphite. If total pressure at equilibrium is 0.8 atm , then Kp is :
Answer
(D)
1.8 atm
9

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A . The amount of the aluminium deposited at the cathode is __________ .

[Given : molar mass of aluminium and chlorine are $27 \mathrm{~g} \mathrm{~mol}^{-1}$ and $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively. Faraday constant $\left.=96500 \mathrm{C} \mathrm{~mol}^{-1}\right]$

Answer
(C)
0.336 g
10

How many different stereoisomers are possible for the given molecule?

JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Basics of Organic Chemistry Question 11 English

Answer
(D)
4
11
A liquid when kept inside a thermally insulated closed vessel at $25^{\circ} \mathrm{C}$ was mechanically stirred from outside. What will be the correct option for the following thermodynamic parameters ?
Answer
(B)
$\Delta \mathrm{U}>0, \mathrm{q}=0, \mathrm{w}>0$
12

Lanthanoid ions with $4 \mathrm{f}^7$ configuration are :

(A) $\mathrm{Eu}^{2+}$

(B) $\mathrm{Gd}^{3+}$

(C) $\mathrm{Eu}^{3+}$

(D) $\mathrm{Tb}^{3+}$

(E) $ \mathrm{Sm}^{2+}$

Choose the correct answer from the options given below :

Answer
(D)
(A) and (B) only
13

The incorrect statements regarding geometrical isomerism are :

(A) Propene shows geometrical isomerism.

(B) Trans isomer has identical atoms/groups on the opposite sides of the double bond.

(C) Cis-but-2-ene has higher dipole moment than trans-but-2-ene.

(D) 2-methylbut-2-ene shows two geometrical isomers.

(E) Trans-isomer has lower melting point than cis isomer.

Choose the correct answer from the options given below :

Answer
(B)
(A), (D) and (E) Only
14

Given below are two statements :

Statement I : One mole of propyne reacts with excess of sodium to liberate half a mole of $\mathrm{H}_2$ gas.

Statement II : Four g of propyne reacts with $\mathrm{NaNH}_2$ to liberate $\mathrm{NH}_3$ gas which occupies 224 mL at STP.

In the light of the above statements, choose the most appropriate answer from the options given below :

Answer
(D)
Statement I is correct but Statement II is incorrect
15
Which of the following electronegativity order is incorrect?
Answer
(C)
$\mathrm{Al}<\mathrm{Mg}<\mathrm{B}<\mathrm{N}$
16

Arrange the following solutions in order of their increasing boiling points.

(i) $10^{-4} \mathrm{M} \mathrm{NaCl}$

(ii) $10^{-4} \mathrm{M}$ Urea

(iii) $10^{-3} \mathrm{M} \mathrm{NaCl}$

(iv) $10^{-2} \mathrm{M} \mathrm{NaCl}$

Answer
(B)
(ii) $<($ i $)<($ iii $)<($ iv $)$
17
In which of the following complexes the CFSE, $\Delta_o$ will be equal to zero?
Answer
(A)
$\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{SCN})_6\right]$
18
Which of the following acids is a vitamin ?
Answer
(B)
Ascorbic acid
19
Radius of the first excited state of Helium ion is given as : $\mathrm{a}_0 \rightarrow$ radius of first stationary state of hydrogen atom.
Answer
(B)
$\mathrm{r}=2 \mathrm{a}_0$
20

The IUPAC name of the following compound is :

JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Basics of Organic Chemistry Question 10 English

Answer
(A)
5-Methoxycarbonly-2-methylhexanoic acid
21

Consider the following sequence of reactions :

JEE Main 2025 (Online) 22nd January Morning Shift Chemistry - Compounds Containing Nitrogen Question 8 English

Molar mass of the product formed $(\mathrm{A})$ is __________ $\mathrm{g} \mathrm{~mol}^{-1}$.

Answer
154
22

The number of molecules/ions that show linear geometry among the following is __________.

$\mathrm{SO}_2, \mathrm{BeCl}_2, \mathrm{CO}_2, \mathrm{~N}_3^{-}, \mathrm{NO}_2, \mathrm{~F}_2 \mathrm{O}, \mathrm{XeF}_2, \mathrm{NO}_2^{+}, \mathrm{I}_3^{-}, \mathrm{O}_3$

Answer
6
23
Some $\mathrm{CO}_2$ gas was kept in a sealed container at a pressure of 1 atm and at 273 K . This entire amount of $\mathrm{CO}_2$ gas was later passed through an aqueous solution of $\mathrm{Ca}(\mathrm{OH})_2$. The excess unreacted $\mathrm{Ca}(\mathrm{OH})_2$ was later neutralized with 0.1 M of 40 mL HCl . If the volume of the sealed container of $\mathrm{CO}_2$ was $x$, then $x$ is ____________ $\mathrm{cm}^3$ (nearest integer). [Given : The entire amount of $\mathrm{CO}_2(\mathrm{~g})$ reacted with exactly half the initial amount of $\mathrm{Ca}(\mathrm{OH})_2$ present in the aqueous solution.]
Answer
45
24
In Carius method for estimation of halogens, 180 mg of an organic compound produced 143.5 mg of AgCl . The percentage composition of chlorine in the compound is _________ %. (Given : molar mass in $\mathrm{g} \mathrm{~mol}^{-1}$ of $\mathrm{Ag}: 108, \mathrm{Cl}: 35.5$ )
Answer
20
25

$\mathrm{A \rightarrow B}$

The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K . If the energy barrier with respect to reactant energy for such isomeric transformation is $191.48 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and the frequency factor is $10^{20}$, the time required for $50 \%$ molecules of A to become B is __________ picoseconds (nearest integer). $\left[\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right]$

Answer
69