JEE Main 2025 Jan 24 Shift 2 — Chemistry

The elemental composition of a compound is 54.2% C, 9.2% H and 36.6% O. If the molar mass of the compound is $132\ \mathrm{g\ mol^{-1}}$, the molecular formula of the compound is :

[Given : The relative atomic mass of $\mathrm{C:H:O = 12:1:16}$]

For hydrogen atom, the orbital/s with lowest energy is/are :

(A) $\mathrm{4s}$ (B) $\mathrm{3p_x}$ (C) $\mathrm{3d_{x^2-y^2}}$ (D) $\mathrm{3d_{z^2}}$ (E) $\mathrm{4p_z}$

Choose the correct answer from the options given below :

Which of the following mixing of 1M base and 1M acid leads to the largest increase in temperature ?

$$\mathrm{S(g)} + \frac{3}{2}\mathrm{O_2(g)} \rightarrow \mathrm{SO_3(g)} + 2x\ \mathrm{kcal}$$

$$\mathrm{SO_2(g)} + \frac{1}{2}\mathrm{O_2(g)} \rightarrow \mathrm{SO_3(g)} + y\ \mathrm{kcal}$$

The heat of formation of $\mathrm{SO_2(g)}$ is given by :

For the reaction, $$\mathrm{H_2(g) + I_2(g) \rightleftharpoons 2HI(g)}$$ Attainment of equilibrium is predicted correctly by :

each option is a plot of molar concentration (y-axis) versus time (x-axis) for the three species $\mathrm{H_2}$, $\mathrm{I_2}$ and $\mathrm{HI}$ approaching equilibrium plateaus

Based on the data given below :

$$\mathrm{E^\circ_{Cr_2O_7^{2-}/Cr^{3+}}} = 1.33\ \mathrm{V} \qquad \mathrm{E^\circ_{Cl_2/Cl^-}} = 1.36\ \mathrm{V}$$

$$\mathrm{E^\circ_{MnO_4^-/Mn^{2+}}} = 1.51\ \mathrm{V} \qquad \mathrm{E^\circ_{Cr^{3+}/Cr}} = -0.74\ \mathrm{V}$$

the strongest reducing agent is :

Given below are two statements :

Statement (I):

a plot of $t_{1/2}$ (y-axis) versus $[R

_0$ (x-axis) shown as a horizontal straight line]* is valid for a first order reaction.

Statement (II):

a plot of $\log\frac{[R

}{[R]_0}$(y-axis) versus time (x-axis) shown as a straight line through the origin with slope$= \frac{k}{2.303}$]* is valid for a first order reaction.

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

Given below are two statements :

Statement (I): Experimentally determined oxygen-oxygen bond lengths in the $\mathrm{O_3}$ are found to be same and the bond length is greater than that of a $\mathrm{O=O}$ (double bond) but less than that of a single $\mathrm{(O-O)}$ bond.

Statement (II): The strong lone pair-lone pair repulsion between oxygen atoms is solely responsible for the fact that the bond length in ozone is smaller than that of a double bond $\mathrm{(O=O)}$ but more than that of a single bond $\mathrm{(O-O)}$.

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

Find the compound 'A' from the following reaction sequences.

\mathrm{A} \xrightarrow{\text{aqua-regia}} \mathrm{B} \xrightarrow[\text{(2) AcOH}]{\text{(1) KNO_2 | NH_4OH}} \text{yellow ppt}

When ethane-1,2-diamine is progressively added to an aqueous solution of nickel(II) chloride, the observed order of colour change will be :

The conditions and consequence that favours the $\mathrm{t_{2g}^3\ e_g^1}$ configuration in a metal complex are :

Match List - I with List - II.

List - I (Transition metal ion)	List - II (Spin only magnetic moment (B.M.))
(A) $\mathrm{Ti^{3+}}$	(I) 3.87
(B) $\mathrm{V^{2+}}$	(II) 0.00
(C) $\mathrm{Ni^{2+}}$	(III) 1.73
(D) $\mathrm{Sc^{3+}}$	(IV) 2.84

Choose the correct answer from the options given below :

Given below are two statements :

Statement (I): The first ionization energy of Pb is greater than that of Sn.

Statement (II): The first ionization energy of Ge is greater than that of Si.

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

The five successive ionization energies of an element are respectively 800, 2427, 3658, 25024 and $32824\ \mathrm{kJ/mol}$. Using the above values, predict the group in which it is present :

In the given structure, number of sp and $\mathrm{sp^2}$ hybridized carbon atoms present respectively are :

an open-chain structure $\mathrm{CH_3-CO-CH=CH-CH_2-C{\equiv}C-CH=CH-C{\equiv}N}$ — a methyl ketone bearing a C=C, then a $\mathrm{CH_2}$, then a $\mathrm{C{\equiv}C}$ triple bond, another C=C, terminating in a nitrile $\mathrm{C{\equiv}N}$

Identify correct statement/s :

(A) $\mathrm{-OCH_3}$ and $\mathrm{-NHCOCH_3}$ are activating group. (B) $\mathrm{-CN}$ and $\mathrm{-OH}$ are meta directing group. (C) $\mathrm{-CN}$ and $\mathrm{-SO_3H}$ are meta directing group. (D) Activating groups act as ortho- and para directing groups. (E) Halides are activating groups.

Choose the correct answer from the options given below :

The structure of the major product formed in the following reaction is :

1-(chloromethyl)-3-bromo-5-iodobenzene (a benzene ring bearing $\mathrm{-CH_2Cl}$, and at the two meta positions an $\mathrm{I}$ and a $\mathrm{Br}$)

$\xrightarrow{\text{AgCN}}$ major product*

Match List - I with List - II.

List - I	List - II
(A) \mathrm{RCN} \xrightarrow[\text{(ii) H_3O^+}]{\text{(i) SnCl_2, HCl}} \mathrm{RCHO}	(I) Etard reaction
(B) \mathrm{C_6H_5COCl} \xrightarrow{\text{H_2 / Pd-BaSO_4}} \mathrm{C_6H_5CHO}	(II) Gatterman-Koch reaction
(C) \mathrm{C_6H_5CH_3} \xrightarrow[\text{(ii) H_3O^+}]{\text{(i) CrO_2Cl_2, CS_2}} \mathrm{C_6H_5CHO}	(III) Rosenmund reduction
(D) \mathrm{C_6H_6} \xrightarrow[\text{(ii) anhydrous AlCl_3 / CuCl}]{\text{(i) CO, HCl}} \mathrm{C_6H_5CHO}	(IV) Stephen reaction

Choose the correct answer from the options given below :

For reaction

aniline (benzene ring with $\mathrm{-NH_2}$) $\rightarrow$ 2-bromoaniline (benzene ring with $\mathrm{-NH_2}$ and an ortho $\mathrm{-Br}$), labelled (Major)

The correct order of set of reagents for the above conversion is :

Match List - I with List - II.

List - I (nitrogenous base) : (A) Adenine (B) Cytosine (C) Thymine (D) Uracil

List - II (structures) : (I)

pyrimidine ring with two C=O groups and an N-H — structure of uracil

(II)

pyrimidine ring with a $\mathrm{CH_3}$ (H_3C) substituent, two C=O groups and an N-H — structure of thymine

(III)

purine ring bearing an $\mathrm{NH_2}$ group — structure of adenine

(IV)

pyrimidine ring bearing an $\mathrm{NH_2}$ group and one C=O — structure of cytosine

Choose the correct answer from the options given below :

The observed and normal molar masses of compound $\mathrm{MX_2}$ are respectively 65.6 and 164. The percentage degree of ionization of $\mathrm{MX_2}$ is _______ % (nearest integer).

Consider a complex reaction taking place in three steps with rate constants $k_1$, $k_2$ and $k_3$ respectively. The overall rate constant $k$ is given by the expression $k = \sqrt{\dfrac{k_1 k_3}{k_2}}$. If the activation energies of the three steps are 60, 30 and $10\ \mathrm{kJ\ mol^{-1}}$ respectively, then the overall energy of activation in $\mathrm{kJ\ mol^{-1}}$ is _______. (Nearest integer)

In Carius method of estimation of halogen, 0.25 g of an organic compound gave 0.15 g of silver bromide (AgBr). The percentage of Bromine in the organic compound is _______ $\times 10^{-1}\%$ (Nearest integer).

(Given : Molar mass of Ag is 108 and Br is $80\ \mathrm{g\ mol^{-1}}$)

The hydrocarbon (X) with molar mass $80\ \mathrm{g\ mol^{-1}}$ and 90% carbon has _______ degree of unsaturation.

The possible number of stereoisomers for 5-phenylpent-4-en-2-ol is _______.