JEE MAIN - Chemistry (2025 - 2nd April Morning Shift)

1

Consider the following compound (X)

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Basics of Organic Chemistry Question 14 English

The most stable and least stable carbon radicals, respectively, produced by homolytic cleavage of corresponding $\mathrm{C}-\mathrm{H}$ bond are :

Answer
(D)
II, I
2

$$\mathrm{CaCO}_3(\mathrm{~s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{CaCl}_2(\mathrm{aq})+\mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l})$$

Consider the above reaction, what mass of $\mathrm{CaCl}_2$ will be formed if 250 mL of 0.76 M HCl reacts with 1000 g of $\mathrm{CaCO}_3$ ?

(Given : Molar mass of $\mathrm{Ca}, \mathrm{C}, \mathrm{O}, \mathrm{H}$ and Cl are $40,12,16,1$ and $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$, respectively)

Answer
(C)
10.545 g
3
If equal volumes of $A B_2$ and $X Y$ (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of $\mathrm{AY}_2$ at 300 K ? (Given $\mathrm{K}_{\mathrm{sp}}\left(\right.$ at 300 K ) for $\mathrm{AY}_2=5.2 \times 10^{-7}$ )
Answer
(B)
$2.0 \times 10^{-2} \mathrm{M} \mathrm{AB}_2, 2.0 \times 10^{-2} \mathrm{M} \mathrm{XY}$
4

Given below are two statements :

Statement (I) : The metallic radius of Al is less than that of Ga .

Statement (II) : The ionic radius of $\mathrm{Al}^{3+}$ is less than that of $\mathrm{Ga}^{3+}$.

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

Answer
(C)
Statement I is incorrect but Statement II is correct
5

Designate whether each of the following compounds is aromatic or not aromatic.

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Basics of Organic Chemistry Question 13 English

Answer
(A)
$a, c, d, e, h$ aromatic and $b, f, g$ not aromatic
6

Choose the correct tests with respective observations.

(A) $\mathrm{CuSO}_4$ (acidified with acetic acid) $+\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right] \rightarrow$ Chocolate brown precipitate.

(B) $\mathrm{FeCl}_3+\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right] \rightarrow$ Prussian blue precipitate.

(C) $\mathrm{ZnCl}_2+\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$, neutralised with $\mathrm{NH}_4 \mathrm{OH} \rightarrow$ White or bluish white precipitate.

(D) $\mathrm{MgCl}_2+\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right] \rightarrow$ Blue precipitate.

(E) $\mathrm{BaCl}_2+\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$, neutralised with $\mathrm{NaOH} \rightarrow$ White precipitate.

Choose the correct answer from the options given below :

Answer
(B)
A, B and C only
7
A solution is made by mixing one mole of volatile liquid $A$ with 3 moles of volatile liquid $B$. The vapour pressure of pure A is 200 mm Hg and that of the solution is 500 mm Hg . The vapour pressure of pure B and the least volatile component of the solution, respectively, are:
Answer
(C)
$600 \mathrm{~mm} \mathrm{~Hg}, \mathrm{A}$
8
A molecule with the formula $\mathrm{AX}_4 \mathrm{Y}$ has all it's elements from p-block. Element A is rarest, monoatomic, non-radioactive from its group and has the lowest ionization enthalpy value among $\mathrm{A}, \mathrm{X}$ and Y . Elements X and Y have first and second highest electronegativity values respectively among all the known elements. The shape of the molecule is:
Answer
(B)
Square pyramidal
9

Given below are two statements :

Statement (I) : In octahedral complexes, when $\Delta_0<\mathrm{P}$ high spin complexes are formed. When $\Delta_0>P$ low spin complexes are formed.

Statement (II) : In tetrahedral complexes because of $\Delta_t

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

Answer
(D)
Both Statement I and Statement II are correct
10
On complete combustion 1.0 g of an organic compound $(\mathrm{X})$ gave 1.46 g of $\mathrm{CO}_2$ and 0.567 g of $\mathrm{H}_2 \mathrm{O}$. The empirical formula mass of compound $(\mathrm{X})$ is __________ g. (Given molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{C}: 12, \mathrm{H}: 1, \mathrm{O}: 16$ )
Answer
(C)
30
11

Given below are two statements:

Statement I : Vanilin JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 11 English 1 will react with NaOH and also with Tollen's reagent.

Statement II : Vanilin JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 11 English 2 will undergo self aldol condensation very easily.

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

Answer
(A)
Statement I is correct but Statement II is incorrect
12
An optically active alkyl halide $\mathrm{C}_4 \mathrm{H}_9 \mathrm{Br}[\mathrm{A}]$ reacts with hot KOH dissolved in ethanol and forms alkene $[B]$ as major product which reacts with bromine to give dibromide $[C]$. The compound [C] is converted into a gas [D] upon reacting with alcoholic $\mathrm{NaNH}_2$. During hydration 18 gram of water is added to 1 mole of gas [D] on warming with mercuric sulphate and dilute acid at 333 K to form compound [E]. The IUPAC name of compound [ E ] is :
Answer
(C)
Butan-2-one
13

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Thermodynamics Question 14 English

Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in water and is allowed to come to thermal equilibrium with water. After opening the stopcock the gas from vessel A expands into vessel B and no change in temperature is observed in the thermometer. Which of the following statement is true ?

Answer
(B)
The pressure in the vessel B before opening the stopcock is zero
14
Among $\mathrm{SO}_2, \mathrm{NF}_3, \mathrm{NH}_3, \mathrm{XeF}_2, \mathrm{ClF}_3$ and $\mathrm{SF}_4$, the hybridization of the molecule with nonzero dipole moment and highest number of lone-pairs of electrons on the central atom is
Answer
(D)
$\mathrm{sp}^3 \mathrm{~d}$
15
Which of the following graph correctly represents the plots of $\mathrm{K}_{\mathrm{H}}$ at 1 bar for gases in water versus temperature?
Answer
(B)
JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Solutions Question 10 English Option 2
16
According to Bohr's model of hydrogen atom, which of the following statement is incorrect?
Answer
(C)
Radius of $6^{\text {th }}$ orbit is three times larger than that of $4^{\text {th }}$ orbit
17
Identify the correct statement among the following :
Answer
(B)
Amino acid, cysteine can easily undergo dimerisation due to the presence of free SH group.
18
The correct order of basic nature in aqueous solution for the bases $\mathrm{NH}_3, \mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2, \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2,\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}$ and $\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}$ is :
Answer
(C)
$\mathrm{NH}_2-\mathrm{NH}_2<\mathrm{NH}_3<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}$
19

The property/properties that show irregularity in first four elements of group-17 is/are

(A) Covalent radius

(B) Electron affinity

(C) Ionic radius

(D) First ionization energy

Choose the correct answer from the options given below :

Answer
(C)
B only
20

Consider the following molecules:

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Chemical Bonding & Molecular Structure Question 10 English

The correct order of rate of hydrolysis is :

Answer
(A)
$\mathrm{p}>\mathrm{q}>\mathrm{r}>\mathrm{s}$
21

For the reaction A $\to$ products.

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 12 English

The concentration of A at 10 minutes is _________ $\times 10^{-3} \mathrm{~mol} \mathrm{~L}^{-1}$ (nearest integer). The reaction was started with $2.5 \mathrm{~mol} \mathrm{~L}^{-1}$ of A .

Answer
2435
22

0.1 mol of the following given antiviral compound $(\mathrm{P})$ will weigh ________ $\times 10^{-1} \mathrm{~g}$ (nearest integer).

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Practical Organic Chemistry Question 8 English

(Given : molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{~N}: 14, \mathrm{O}: 16, \mathrm{~F}: 19, \mathrm{I}: 127$ )

Answer
372
23

Consider the following electrochemical cell at standard condition.

$$\mathrm{Au}(\mathrm{~s})\left|\mathrm{QH}_2, \mathrm{Q}\right| \mathrm{NH}_4 \mathrm{X}(0.01 \mathrm{M})| | \mathrm{Ag}^{+}(1 \mathrm{M}) \mid \mathrm{Ag}(\mathrm{~s}) \mathrm{E}_{\text {cell }}=+0.4 \mathrm{~V}$$

The couple $\mathrm{QH}_2 / \mathrm{Q}$ represents quinhydrone electrode, the half cell reaction is given below:

JEE Main 2025 (Online) 2nd April Morning Shift Chemistry - Electrochemistry Question 8 English

$$\left[\text { Given : } \mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}^0=+0.8 \mathrm{~V} \text { and } \frac{2.303 \mathrm{RT}}{\mathrm{~F}}=0.06 \mathrm{~V}\right]$$

The $\mathrm{pK}_{\mathrm{b}}$ value of the ammonium halide salt $\left(\mathrm{NH}_4 \mathrm{X}\right)$ used here is __________ . (nearest integer)

Answer
6
24

Consider the following equilibrium,

$$\mathrm{CO}(\mathrm{~g})+2 \mathrm{H}_2(\mathrm{~g}) \rightleftharpoons \mathrm{CH}_3 \mathrm{OH}(\mathrm{~g})$$

0.1 mol of CO along with a catalyst is present in a $2 \mathrm{dm}^3$ flask maintained at 500 K . Hydrogen is introduced into the flask until the pressure is 5 bar and 0.04 mol of $\mathrm{CH}_3 \mathrm{OH}$ is formed. The $K_p^\theta$ is __________ $\times 10^{-3}$ (nearest integer).

Given : $\mathrm{R}=0.08 \mathrm{~dm}^3$ bar $\mathrm{K}^{-1} \mathrm{~mol}^{-1}$

Assume only methanol is formed as the product and the system follows ideal gas behaviour.

Answer
74
25
A transition metal (M) among $\mathrm{Mn}, \mathrm{Cr}, \mathrm{Co}$ and Fe has the highest standard electrode potential $\left(\mathrm{M}^{3+} / \mathrm{M}^{2+}\right)$. It forms a metal complex of the type $\left[\mathrm{M}(\mathrm{CN})_6\right]^{4-}$. The number of electrons present in the $\mathrm{e}_{\mathrm{g}}$ orbital of the complex is ___________.
Answer
1