JEE MAIN - Chemistry (2025 - 4th April Morning Shift)

1

For $\mathrm{A}_2+\mathrm{B}_2 \rightleftharpoons 2 \mathrm{AB}$

$\mathrm{E}_{\mathrm{a}}$ for forward and backward reaction are 180 and $200 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively

If catalyst lowers $\mathrm{E}_{\mathrm{a}}$ for both reaction by $100 \mathrm{~kJ} \mathrm{~mol}^{-1}$.

Which of the following statement is correct?

Answer
(A)
Catalyst does not alter the Gibbs energy change of a reaction.
2

Predict the major product of the following reaction sequence:-

JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Hydrocarbons Question 1 English

Answer
(B)
JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Hydrocarbons Question 1 English Option 2
3

Which one of the following about an electron occupying the 1 s orbital in a hydrogen atom is incorrect?

(Bohr's radius is represented by $\mathrm{a}_0$)

Answer
(B)
The total energy of the electron is maximum when it is at a distance $a_0$ from the nucleus
4

Rate law for a reaction between $A$ and $B$ is given by

$$\mathrm{r}=\mathrm{k}[\mathrm{~A}]^{\mathrm{n}}[\mathrm{~B}]^{\mathrm{m}}$$

If concentration of $A$ is doubled and concentration of $B$ is halved from their initial value, the ratio of new rate of reaction to the initial rate of reaction $\left(\frac{r_2}{r_1}\right)$ is

Answer
(B)
$2^{(\mathrm{n}-m)}$
5
Pair of transition metal ions having the same number of unpaired electrons is
Answer
(D)
$\mathrm{V}^{2+}, \mathrm{Co}^{2+}$
6
On charging the lead storage battery, the oxidation state of lead changes from $x_1$ to $y_1$ at the anode and from $x_2$ to $y_2$ at the cathode. The values of $x_1, y_1, x_2, y_2$ are respectively :
Answer
(D)
$+2,0,+2,+4$
7
Aldol condensation is a popular and classical method to prepare $\alpha, \beta$-unsaturated carbonyl compounds. This reaction can be both intermolecular and intramolecular. Predict which one of the following is not a product of intramolecular aldol condensation?
Answer
(B)
JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 3 English Option 2
8
Benzene is treated with oleum to produce compound $(\mathrm{X})$ which when further heated with molten sodium hydroxide followed by acidification produces compound $(\mathrm{Y})$. The compound Y is treated with zinc metal to produce compound $(Z)$. Identify the structure of compound $(Z)$ from the following option.
Answer
(C)
JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Alcohols, Phenols and Ethers Question 1 English Option 3
9

One mole of an ideal gas expands isothermally and reversibly from $10 \mathrm{dm}^3$ to $20 \mathrm{dm}^3$ at 300 K . $\Delta \mathrm{U}, \mathrm{q}$ and work done in the process respectively are

Given: $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$

$\ln 10=2.3$

$\log 2=0.30$

$$\log 3=0.48$$

Answer
(C)
$0,1.718 \mathrm{~kJ},-1.718 \mathrm{~kJ}$
10

Given below are two statements.

JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Chemical Bonding & Molecular Structure Question 3 English

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

Answer
(B)
Statement I is true but Statement II is false
11
Which one of the following complexes will have $\Delta_{\mathrm{o}}=0$ and $\mu=5.96$ B.M?
Answer
(B)
$\left[\mathrm{Mn}(\mathrm{SCN})_6\right]^{4-}$
12

The major product (A) formed in the following reaction sequence is

JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Compounds Containing Nitrogen Question 2 English

Answer
(B)
JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Compounds Containing Nitrogen Question 2 English Option 2
13

Given below are two statements:

Statement I: Nitrogen forms oxides with +1 to +5 oxidation states due to the formation of $\mathrm{p} \pi-\mathrm{p} \pi$ bond with oxygen.

Statement II: Nitrogen does not form halides with +5 oxidation state due to the absence of d-orbital in it.

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

Answer
(A)
Both Statement I and Statement II are true
14
Number of stereoisomers possible for the complexes, $\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]$ and $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$ are respectively $(p y=$ pyridine,$o x=$ oxalate $)$
Answer
(B)
2 & 3
15
An organic compound $(\mathrm{X})$ with molecular formula $\mathrm{C}_3 \mathrm{H}_6 \mathrm{O}$ is not readily oxidised. On reduction it gives $\mathrm{C}_3 \mathrm{H}_8 \mathrm{O}(\mathrm{Y})$ which reacts with HBr to give a bromide $(\mathrm{Z})$ which is converted to Grignard reagent. This Grignard reagent on reaction with $(\mathrm{X})$ followed by hydrolysis give 2,3-dimethylbutan-2-ol. Compounds $(\mathrm{X}),(\mathrm{Y})$ and $(\mathrm{Z})$ respectively are:
Answer
(B)
$\mathrm{CH}_3 \mathrm{COCH}_3, \mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3, \mathrm{CH}_3 \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_3$
16
Let us consider a reversible reaction at temperature, T. In this reaction, both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ were observed to have positive values. If the equilibrium temperature is Te , then the reaction becomes spontaneous at:
Answer
(B)
$\mathrm{T}>\mathrm{Te}$
17

Which of the following molecule(s) show/s paramagnetic behavior?

A. $\mathrm{O}_2$

B. $\mathrm{N}_2$

C. $\mathrm{F}_2$

D. $\mathrm{S}_2$

E. $\mathrm{Cl}_2$

Choose the correct answer from the options given below:

Answer
(C)
A & D Only
18
Identify the pair of reactants that upon reaction, with elimination of HCl will give rise to the dipeptide Gly-Ala.
Answer
(C)
JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Biomolecules Question 3 English Option 3
19
Given below are the pairs of group 13 elements showing their relation in terms of atomic radius. $(\mathrm{B}<\mathrm{Al}),(\mathrm{Al}<\mathrm{Ga}),(\mathrm{Ga}<\mathrm{In})$ and $(\mathrm{In}<\mathrm{Tl})$ Identify the elements present in the incorrect pair and in that pair find out the element (X) that has higher ionic radius $\left(\mathrm{M}^{3+}\right)$ than the other one. The atomic number of the element $(\mathrm{X})$ is
Answer
(C)
31
20

$X Y$ is the membrane/partition between two chambers 1 and 2 containing sugar solutions of concentration $c_1$ and $c_2\left(c_1>c_2\right) \mathrm{mol} \mathrm{L}^{-1}$. For the reverse osmosis to take place identify the correct condition.

(Here $p_1$ and $p_2$ are pressures applied on chamber 1 and 2 ).

JEE Main 2025 (Online) 4th April Morning Shift Chemistry - Solutions Question 1 English

A. Membrane/Partition : Cellophane, $\mathrm{p}_1>\pi$

B. Membrane/Partition : Porous, $\mathrm{p}_2>\pi$

C. Membrane/Partition : Parchment paper, $p_1>\pi$

D. Membrane/Partition : Cellophane, $\mathrm{p}_2>\pi$

Choose the correct answer from the option given below:

Answer
(A)
A and C Only
21
The pH of a 0.01 M weak acid $\mathrm{HX}\left(\mathrm{K}_a=4 \times 10^{-10}\right)$ is found to be 5 . Now the acid solution is diluted with excess of water so that the pH of the solution changes to 6 . The new concentration of the diluted weak acid is given as $x \times 10^{-4} \mathrm{M}$. The value of $x$ is _________ (nearest integer)
Answer
25
22

In Dumas' method for estimation of nitrogen 1 g of an organic compound gave 150 mL of nitrogen collected at 300 K temperature and 900 mm Hg pressure. The percentage composition of nitrogen in the compound is _______ % (nearest integer)

(Aqueous tension at $300 \mathrm{~K}=15 \mathrm{~mm} \mathrm{~Hg}$ )

Answer
20
23

Fortification of food with iron is done using $\mathrm{FeSO}_4 \cdot 7 \mathrm{H}_2 \mathrm{O}$. The mass in grams of the $\mathrm{FeSO}_4$. $7 \mathrm{H}_2 \mathrm{O}$ required to achieve 12 ppm of iron in 150 kg of wheat is ______ (Nearest integer)

[Given: Molar mass of $\mathrm{Fe}, \mathrm{S}$ and and O respectively are 56, 32 and $16 \mathrm{~g} \mathrm{~mol}^{-1}$ ]

Answer
9
24
$\mathrm{KMnO}_4$ acts as an oxidising agent in acidic medium. ' X ' is the difference between the oxidation states of Mn in reactant and product. ' Y ' is the number of ' d ' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of $\mathrm{X}+\mathrm{Y}$ is __________.
Answer
10
25

The total number of hydrogen bonds of a DNA-double Helix strand whose one strand has the following sequence of bases is ________.

$$5^{\prime}-\mathrm{G}-\mathrm{G}-\mathrm{C}-\mathrm{A}-\mathrm{A}-\mathrm{A}-\mathrm{T}-\mathrm{C}-\mathrm{G}-\mathrm{G}-\mathrm{C}-\mathrm{T}-\mathrm{A}-3^{\prime}$$

Answer
33