JEE Main 2025 Jan 23 Shift 1 — Chemistry

After removal of $10^{21}$ molecules from '$x$' mg sample of $\mathrm{CO_2}$, $2.8 \times 10^{-3}$ mol of it are left. The mass of $\mathrm{CO_2}$ taken initially is :

Given : $\mathrm{N_A} = 6.02 \times 10^{23}\ \mathrm{mol^{-1}}$

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 $\mathrm{R_H} = 10^5\ \mathrm{cm^{-1}}$, $h = 6.6 \times 10^{-34}$ J s, $c = 3 \times 10^8$ m/s)

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.	$\mathrm{NO,\ NO_2}$
B.	Molecules with incomplete octet	II.	$\mathrm{BCl_3,\ AlCl_3}$
C.	Molecules with incomplete octet with odd electron	III.	$\mathrm{H_2SO_4,\ PCl_5}$
D.	Molecules with expanded octet	IV.	$\mathrm{CCl_4,\ CO_2}$

Choose the correct answer from the options given below:

Ice at $-5°\mathrm{C}$ is heated to become vapor with temperature of $110°\mathrm{C}$ at atmospheric pressure. The entropy change associated with this process can be obtained from

$\mathrm{CrCl_3.xNH_3}$ can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of $0.558°\mathrm{C}$. Assuming 100% ionisation of this complex and coordination number of Cr is 6, the complex will be

(Given $\mathrm{K_f} = 1.86$ K kg mol$^{-1}$)

Which of the following happens when $\mathrm{NH_4OH}$ is added gradually to the solution containing 1M $\mathrm{A^{2+}}$ and 1M $\mathrm{B^{3+}}$ ions?

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

$$\mathrm{FeO_4^{2-}} \xrightarrow{+2.0\ \mathrm{V}} \mathrm{Fe^{3+}} \xrightarrow{0.8\ \mathrm{V}} \mathrm{Fe^{2+}} \xrightarrow{-0.5\ \mathrm{V}} \mathrm{Fe^{0}}$$

In the above diagram, the standard electrode potentials are given in volts (over the arrow). The value of $E^{\ominus}_{\mathrm{FeO_4^{2-}}/\mathrm{Fe^{2+}}}$ is

The element, which does not occur in the same period as the other elements (modern periodic table):

The incorrect statement among the following is

The correct set of ions (aqueous solution) with same colour from the following is:

The d– electronic configuration of an octahedral Co(II) complex having magnetic moment of 3.95 BM is:

The complex that shows Facial - Meridional isomerism is:

On chlorination under photochemical conditions, propane molecule gives two dichloro products "x" and "y". Among "x" and "y", "x" is an optically active molecule. How many trichloro products (consider structural isomers only) will be obtained from "x" when it is treated with chlorine again under photochemical conditions?

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

three ring structures — p: cyclopropenyl anion (three-membered ring with one C=C and a negative charge), q: cyclopentadienyl anion (five-membered ring with two C=C, an H and a negative charge on the sp³ carbon), r: cyclooctatetraene (eight-membered ring with four alternating C=C)

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:

What amount of bromine will be required to convert 2 g of phenol into 2,4,6-tribromophenol?

(Given molar masses in g mol$^{-1}$ of C, H, O, Br are 12, 1, 16 and 80 respectively)

The major product of the following reaction is:

$$\mathrm{CH_3CH_2CH{=}O} \xrightarrow[\text{reflux}]{\substack{\text{excess HCHO} \\ \text{alkali}}} ?$$

Which among the following react with Hinsberg's reagent?

A. $\mathrm{C_6H_5{-}NH_2}$ (aniline)

B. $\mathrm{C_6H_5{-}N(CH_3)_2}$ (N,N-dimethylaniline)

C. $\mathrm{CH_3{-}NH_2}$

D. $\mathrm{N(CH_3)_3}$

E. $\mathrm{(C_6H_5)_2NH}$ (diphenylamine)

Choose the correct answer from the options given below:

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

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 $\mathrm{Na_4[Fe(CN)_6]}$

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

The standard enthalpy and standard entropy of decomposition of $\mathrm{N_2O_4}$ to $\mathrm{NO_2}$ are 55.0 kJ mol$^{-1}$ and 175.0 J/K/mol respectively. The standard free energy change for this reaction at 25°C in J mol$^{-1}$ is _____ (Nearest integer)

If 1 mM solution of ethylamine produces $\mathrm{pH} = 9$, then the ionization constant ($\mathrm{K_b}$) 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.]

For the thermal decomposition reaction of $\mathrm{N_2O_5(g)}$ mentioned below, at constant volume, the following table can be created.

$$\mathrm{2N_2O_5(g) \rightarrow 2N_2O_4(g) + O_2(g)}$$

S.No.	Time (s)	Total pressure (atm)
1	0	0.6
2	100	'x'

$x =$ _____ $\times 10^{-3}$ atm (nearest integer)

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

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

3-nitrotoluene (benzene ring with $\mathrm{CH_3}$ group and $\mathrm{NO_2}$ at the meta position)

$$\xrightarrow{\substack{\text{i) } \mathrm{Br_2},\ \mathrm{Fe} \\ \text{ii) } \mathrm{Sn}, \mathrm{HCl} \\ \text{iii) } \mathrm{NaNO_2}, \mathrm{HCl}, 273\,\mathrm{K} \\ \text{iv) } \mathrm{H_3PO_2}, \mathrm{H_2O}}} \text{(A) Major Product}$$

Molar mass of product (A) is _____ g mol$^{-1}$.

(Given molar mass in g mol$^{-1}$ of C : 12, H: 1, O :16, Br : 80, N : 14, P :31)

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 g mol$^{-1}$ of Ba : 137, S : 32, O : 16)