JEE Main 2025 Apr 7 Shift 2 — Chemistry

The extra stability of half-filled subshell is due to :

(A) Symmetrical distribution of electrons

(B) Smaller coulombic repulsion energy

(C) The presence of electrons with the same spin in non-degenerate orbitals

(D) Larger exchange energy

(E) Relatively smaller shielding of electrons by one another

Identify the correct statements :

The correct statement amongst the following is :

The hydration energies of $\mathrm{K^+}$ and $\mathrm{Cl^-}$ are $-x$ and $-y$ kJ/mol respectively. If lattice energy of KCl is $-z$ kJ/mol, then the heat of solution of KCl is :

Match List - I with List - II.

List - I	List - II
(A) Solution of chloroform and acetone	(I) Minimum boiling azeotrope
(B) Solution of ethanol and water	(II) Dimerizes
(C) Solution of benzene and toluene	(III) Maximum boiling azeotrope
(D) Solution of acetic acid in benzene	(IV) $\Delta \mathrm{V_{mix}} = 0$

Choose the correct answer from the options given below :

Liquid A and B form an ideal solution. The vapour pressures of pure liquids A and B are 350 and 750 mm Hg respectively at the same temperature. If $x_A$ and $x_B$ are the mole fraction of A and B in solution while $y_A$ and $y_B$ are the mole fraction of A and B in vapour phase then,

Given below are two statements :

1 M aqueous solutions of each of $\mathrm{Cu(NO_3)_2}$, $\mathrm{AgNO_3}$, $\mathrm{Hg_2(NO_3)_2}$, $\mathrm{Mg(NO_3)_2}$ are electrolysed using inert electrodes. Given : $\mathrm{E^{\theta}_{Ag^+/Ag}} = 0.80\ \mathrm{V}$, $\mathrm{E^{\theta}_{Hg_2^{2+}/Hg}} = 0.79\ \mathrm{V}$, $\mathrm{E^{\theta}_{Cu^{2+}/Cu}} = 0.24\ \mathrm{V}$ and $\mathrm{E^{\theta}_{Mg^{2+}/Mg}} = -2.37\ \mathrm{V}$.

Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be Ag, Hg and Cu.

Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.

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

$\mathrm{A(g) \rightarrow B(g) + C(g)}$ is a first order reaction.

Time	$t$	$\infty$
$\mathrm{p_{system}}$	$\mathrm{p_t}$	$\mathrm{p_\infty}$

The reaction was started with reactant A only. Which of the following expression is correct for rate constant $k$ ?

In $\mathrm{SO_2}$, $\mathrm{NO_2^-}$ and $\mathrm{N_3^-}$ the hybridizations at the central atom are respectively :

Choose the incorrect trend in the atomic radii ($r$) of the elements.

The correct statements from the following are :

(A) $\mathrm{Tl^{3+}}$ is a powerful oxidising agent

(B) $\mathrm{Al^{3+}}$ does not get reduced easily

(C) Both $\mathrm{Al^{3+}}$ and $\mathrm{Tl^{3+}}$ are very stable in solution

(D) $\mathrm{Tl^+}$ is more stable than $\mathrm{Tl^{3+}}$

(E) $\mathrm{Al^{3+}}$ and $\mathrm{Tl^+}$ are highly stable

Choose the correct answer from the options given below :

'X' is the number of acidic oxides among $\mathrm{VO_2}$, $\mathrm{V_2O_3}$, $\mathrm{CrO_3}$, $\mathrm{V_2O_5}$ and $\mathrm{Mn_2O_7}$. The primary valency of cobalt in $\mathrm{[Co(H_2NCH_2CH_2NH_2)_3]_2(SO_4)_3}$ is Y. The value of $X + Y$ is __________.

The number of unpaired electrons responsible for the paramagnetic nature of the following complex species are respectively :

$\mathrm{[Fe(CN)_6]^{3-}}$, $\mathrm{[FeF_6]^{3-}}$, $\mathrm{[CoF_6]^{3-}}$, $\mathrm{[Mn(CN)_6]^{3-}}$

Match List - I with List - II.

List - I (Complex)	List - II (Primary valency and Secondary valency)
(A) $\mathrm{[Co(en)_2Cl_2]Cl}$	(I) 3, 6
(B) $\mathrm{[Pt(NH_3)_2Cl(NO_2)]}$	(II) 3, 4
(C) $\mathrm{Hg[Co(SCN)_4]}$	(III) 2, 6
(D) $\mathrm{[Mg(EDTA)]^{2-}}$	(IV) 2, 4

Choose the correct answer from the options given below :

Mixture of 1 g each of chlorobenzene, aniline and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel. 5 M NaOH (30 mL) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains :

Given below are two statements :

Statement (I) : (Z)-1,2-dichloroethene ($cis$ $\mathrm{CHCl=CHCl}$) is more polar than (Z)-1,2-dibromoethene ($cis$ $\mathrm{CHBr=CHBr}$).

Statement (II) : Boiling point of (E)-1,2-dibromoethene ($trans$ $\mathrm{CHBr=CHBr}$) is lower than (Z)-1,2-dibromoethene ($cis$ $\mathrm{CHBr=CHBr}$) but it is more polar than (Z)-1,2-dibromoethene ($cis$ $\mathrm{CHBr=CHBr}$).

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

Statement I compares cis-CHCl=CHCl with cis-CHBr=CHBr; Statement II compares trans-CHBr=CHBr with cis-CHBr=CHBr

The number of optically active products obtained from the complete ozonolysis of the given compound is :

$\mathrm{H_3C-CH=CH-C^*(CH_3)(H)-CH=CH-C^*(H)(CH_3)-CH=CH-CH_3}$, a triene with two stereocentres (the first bearing wedge-CH$_3$/hash-H, the second bearing wedge-H/hash-CH$_3$)

Match List - I with List - II.

List - I (Conversion)	List - II (Reagents, Conditions used)
(A) Chlorobenzene $\rightarrow$ phenol	(I) Warm, $\mathrm{H_2O}$
(B) 4-chloronitrobenzene $\rightarrow$ 4-nitrophenol	(II) (a) NaOH, 368K; (b) $\mathrm{H_3O^+}$
(C) 1-chloro-2,4-dinitrobenzene $\rightarrow$ 2,4-dinitrophenol	(III) (a) NaOH, 443K; (b) $\mathrm{H_3O^+}$
(D) 2-chloro-1,3,5-trinitrobenzene (picryl chloride) $\rightarrow$ 2,4,6-trinitrophenol (picric acid)	(IV) (a) NaOH, 623K, 300 atm; (b) $\mathrm{H_3O^+}$

Choose the correct answer from the options given below :

structures showing aryl chloride to phenol conversions in List-I

"P" is an optically active compound with molecular formula $\mathrm{C_6H_{12}O}$. When 'P' is treated with 2,4-dinitrophenylhydrazine, it gives a positive test. However, in presence of Tollens reagent, "P" gives a negative test. Predict the structure of "P".

The descending order of basicity of following amines is :

(A) aniline ($\mathrm{C_6H_5NH_2}$)

(B) 4-methoxyaniline ($\mathrm{4\text{-}MeO\text{-}C_6H_4NH_2}$)

(C) 4-nitroaniline ($\mathrm{4\text{-}O_2N\text{-}C_6H_4NH_2}$)

(D) $\mathrm{CH_3NH_2}$

(E) $\mathrm{(CH_3)_2NH}$

Choose the correct answer from the options given below :

Given below are two statements :

Statement (I) : On hydrolysis, oligo peptides give rise to fewer number of $\alpha$-amino acids while proteins give rise to a large number of $\beta$-amino acids.

Statement (II) : Natural proteins are denatured by acids which convert the water soluble form of fibrous proteins to their water insoluble form.

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

Butane reacts with oxygen to produce carbon dioxide and water following the equation given below.

$$\mathrm{C_4H_{10}(g) + \frac{13}{2}O_2(g) \rightarrow 4CO_2(g) + 5H_2O(l)}$$

If 174.0 kg of butane is mixed with 320.0 kg of $\mathrm{O_2}$, the volume of water formed in liters is __________. (Nearest integer)

[Given : (a) Molar mass of C, H, O are 12, 1, 16 $\mathrm{g\ mol^{-1}}$ respectively, (b) Density of water = $1\ \mathrm{g\ mL^{-1}}$]

One litre buffer solution was prepared by adding 0.10 mol each of $\mathrm{NH_3}$ and $\mathrm{NH_4Cl}$ in deionised water. The change in pH on addition of 0.05 mol of HCl to the above solution is __________ $\times 10^{-2}$. (Nearest integer)

Given : $\mathrm{p}K_b$ of $\mathrm{NH_3} = 4.745$ and $\log_{10} 3 = 0.477$

The number of paramagnetic metal complex species among $\mathrm{[Co(NH_3)_6]^{3+}}$, $\mathrm{[Co(C_2O_4)_3]^{3-}}$, $\mathrm{[MnCl_6]^{3-}}$, $\mathrm{[Mn(CN)_6]^{3-}}$, $\mathrm{[CoF_6]^{3-}}$, $\mathrm{[Fe(CN)_6]^{3-}}$ and $\mathrm{[FeF_6]^{3-}}$ with same number of unpaired electrons is __________.

In Dumas' method 292 mg of an organic compound released 50 mL of nitrogen gas ($\mathrm{N_2}$) at 300 K temperature and 715 mm Hg pressure. The percentage composition of 'N' in the organic compound is __________% (Nearest integer)

(Aqueous tension at 300 K = 15 mm Hg)

Identify the structure of the final product (D) in the following sequence of the reactions :

$$\mathrm{Ph-CO-CH_3} \xrightarrow[\Delta]{\mathrm{PCl_5}} A \xrightarrow{\mathrm{3\ eq.\ NaNH_2/NH_3}} B \xrightarrow{\text{Acidify}} C \xrightarrow{\substack{1.\ \mathrm{B_2H_6} \\ 2.\ \mathrm{H_2O_2/OH^-}}} D$$

Total number of $sp^2$ hybridised carbon atoms in product D is __________.