JEE Main 2025 Apr 2 Shift 1 — Chemistry

$\mathrm{CaCO_3(s) + 2HCl(aq) \rightarrow CaCl_2(aq) + CO_2(g) + H_2O(l)}$

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 Ca, C, O, H and Cl are 40, 12, 16, 1 and 35.5 $\mathrm{g\ mol^{-1}}$, respectively)

According to Bohr's model of hydrogen atom, which of the following statement is incorrect ?

two vessels B and A connected by a stopcock, immersed in a water bath fitted with a thermometer and a stirrer

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 ?

Which of the following graph correctly represents the plots of $K_H$ at 1 bar for gases in water versus temperature?

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 :

If equal volumes of $\mathrm{AB_2}$ and XY (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of $\mathrm{AY_2}$ at 300 K ?

(Given $K_{sp}$ (at 300 K) for $\mathrm{AY_2} = 5.2 \times 10^{-7}$)

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 non-zero dipole moment and highest number of lone-pairs of electrons on the central atom is :

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 :

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 :

Given below are two statements :

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

Statement (II) : In tetrahedral complexes because of $\Delta_t < P$, low spin complexes are rarely formed.

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

A molecule with the formula $\mathrm{AX_4Y}$ 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 A, 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 :

Choose the correct tests with respective observations.

(A) $\mathrm{CuSO_4}$ (acidified with acetic acid) $+ \mathrm{K_4[Fe(CN)_6]} \rightarrow$ Chocolate brown precipitate. (B) $\mathrm{FeCl_3} + \mathrm{K_4[Fe(CN)_6]} \rightarrow$ Prussian blue precipitate. (C) $\mathrm{ZnCl_2} + \mathrm{K_4[Fe(CN)_6]}$, neutralised with $\mathrm{NH_4OH} \rightarrow$ White or bluish white precipitate. (D) $\mathrm{MgCl_2} + \mathrm{K_4[Fe(CN)_6]} \rightarrow$ Blue precipitate. (E) $\mathrm{BaCl_2} + \mathrm{K_4[Fe(CN)_6]}$, neutralised with NaOH $\rightarrow$ White precipitate.

Choose the correct answer from the options given below :

On complete combustion 1.0 g of an organic compound (X) gave 1.46 g of $\mathrm{CO_2}$ and 0.567 g of $\mathrm{H_2O}$. The empirical formula mass of compound (X) is __________ g.

(Given molar mass in $\mathrm{g\ mol^{-1}}$ C : 12, H : 1, O : 16)

Consider the following compound (X)

$$\mathrm{H-\overset{I}{C}\equiv C-\overset{II}{C}H_2-\overset{III}{\underset{\underset{CH_3}{|}}{C}}H-\overset{IV}{C}H_3}$$

(X)

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

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

eight ring structures — (a) cyclopentadienyl anion; (b) cyclopentadienyl cation; (c) cyclobutadienyl dication (four-membered ring with two + charges); (d) cyclobutadienyl dianion (four-membered ring with two − charges); (e) cycloheptatrienyl (tropylium) cation; (f) cyclooctatetraene; (g) cyclobutadiene; (h) cyclopropenyl cation

An optically active alkyl halide $\mathrm{C_4H_9Br}$ [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 :

Consider the following molecules :

(p) $\mathrm{CH_3-CH_2-\overset{\overset{O}{\|}}{C}-Cl}$ (q) $\mathrm{CH_3-CH_2-\overset{\overset{O}{\|}}{C}-O-\overset{\overset{O}{\|}}{C}-CH_3}$

(r) $\mathrm{CH_3-CH_2-\overset{\overset{O}{\|}}{C}-O-CH_2-CH_3}$ (s) $\mathrm{CH_3-CH_2-\overset{\overset{O}{\|}}{C}-NH_2}$

The correct order of rate of hydrolysis is :

Given below are two statements :

Statement (I) : Vanillin

4-hydroxy-3-methoxybenzaldehyde structure

will react with NaOH and also with Tollen's reagent.

Statement (II) : Vanillin

4-hydroxy-3-methoxybenzaldehyde structure

will undergo self aldol condensation very easily.

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

The correct order of basic nature in aqueous solution for the bases $\mathrm{NH_3}$, $\mathrm{H_2N-NH_2}$, $\mathrm{CH_3CH_2NH_2}$, $\mathrm{(CH_3CH_2)_2NH}$ and $\mathrm{(CH_3CH_2)_3N}$ is :

Identify the correct statement among the following :

Consider the following electrochemical cell at standard condition.

$$\mathrm{Au(s)\,|\,QH_2, Q\,|\,NH_4X(0.01\ M)\,||\,Ag^+(1\ M)\,|\,Ag(s)} \quad E_{cell} = +0.4\ \mathrm{V}$$

The couple $\mathrm{QH_2/Q}$ represents quinhydrone electrode, the half cell reaction is given below :

p-benzoquinone (Q) $+ 2e^- + 2H^+ \rightarrow$ hydroquinone (QH$_2$)

$\quad E^{\circ}_{Q/QH_2} = +0.7\ \mathrm{V}$

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

The $pK_b$ value of the ammonium halide salt ($\mathrm{NH_4X}$) used here is __________. (nearest integer)

For the reaction A $\rightarrow$ products.

straight-line plot of $\dfrac{t_{1/2}}{\text{min}}$ versus $[A

_0/\mathrm{mol\ L^{-1}}$ through the origin, slope = 76.92 (appropriate units)]*

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

Consider the following equilibrium,

$$\mathrm{CO(g) + 2H_2(g) \rightleftharpoons CH_3OH(g)}$$

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 $\mathrm{CH_3OH}$ is formed. The $K_p^{\theta}$ is __________ $\times 10^{-3}$ (nearest integer).

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

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

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

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

nucleoside structure (P) — a 5-iodouracil (pyrimidine-2,4-dione with I at C5, NH at N3) attached via N1 to a furanose sugar ring bearing HOCH$_2$ at C4', OH at C3', F at C2'

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