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Chemistry

The element that does not belong to the same period of the remaining elements (modern periodic table) is:

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

Which of the following happens when \( \mathrm{NH_4OH} \) is added gradually to the solution containing \( 1 \, \text{M} \) \( A^{2+} \) and \( 1 \, \text{M} \) \( B^{3+} \) ions? Given: \( K_{sp}[A(OH)_2] = 9 \times 10^{-10} \) and \( K_{sp}[B(OH)_3] = 27 \times 10^{-18} \) at \( 298 \, \text{K} \).

Propane molecule on chlorination under photochemical condition gives two di-chloro products, “x” and “y”. Amongst “x” and “y”, “x” is an optically active molecule. How many tri-chloro products (consider only structural isomers) will be obtained from “x” when it is further treated with chlorine under the photochemical condition?

The major product of the following reaction is: \( \mathrm{CH_3CH_2CH{=}O} \xrightarrow[\text{reflux}]{\text{excess } \mathrm{HCHO}\ \text{alkali}} \ ? \)

Match the LIST-I with LIST-II.

Choose the correct answer from the options given below:

Match the LIST-I with LIST-II.

Choose the correct answer from the options given below:

The d-electronic configuration of an octahedral Co(II) complex having magnetic moment of \( 3.95 \ \text{BM} \) is:

Heat treatment of muscular pain involves radiation of wavelength of about \( 900 \ \text{nm} \). Which spectral line of H atom is suitable for this?
Given: Rydberg constant \( R_H = 10^5 \ \text{cm}^{-1} \), \( h = 6.6 \times 10^{-34} \ \text{J s} \), \( c = 3 \times 10^8 \ \text{m/s} \)

What amount of bromine will be required to convert \( 2 \ \text{g} \) of phenol into \( 2,4,6 \)-tribromophenol?
(Given molar mass in \( \text{g mol}^{-1} \) of C, H, O, Br are \( 12 \), \( 1 \), \( 16 \), \( 80 \) respectively)

\( \mathrm{FeO_4^{2-}} \; \overset{+2.0\,\text{V}}{\longrightarrow} \; \mathrm{Fe^{3+}} \; \overset{0.8\,\text{V}}{\longrightarrow} \; \mathrm{Fe^{2+}} \; \overset{-0.5\,\text{V}}{\longrightarrow} \; \mathrm{Fe^0} \)
In the above diagram, the standard electrode potentials are given in volts (over the arrow).

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

\( \mathrm{CrCl_3.xNH_3} \) can exist as a complex. \( 0.1 \) molal aqueous solution of this complex shows a depression in freezing point of \( 0.558^\circ \text{C} \). Assuming \( 100\% \) ionisation of this complex and coordination number of \( \mathrm{Cr} \) is \( 6 \), the complex will be (Given \( K_f = 1.86 \, \text{K kg mol}^{-1} \) )

Which among the following react with Hinsberg's reagent?

Choose the correct answer from options given below:

The incorrect statement among the following is:

Ice at \( -5^\circ \text{C} \) is heated to become vapor with temperature of \( 110^\circ \text{C} \) at atmospheric pressure. The entropy change associated with this process can be obtained from:

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

\( 2.8 \times 10^{-3} \, \text{mol} \) of \( \mathrm{CO_2} \) is left after removing \( 10^{21} \) molecules from its '\( x \)' \( \text{mg} \) sample. The mass of \( \mathrm{CO_2} \) taken initially is:
[Given: \( N_A = 6.02 \times 10^{23} \, \text{mol}^{-1} \)]

The complex that shows Facial – Meridional isomerism is:

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

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

Molar mass of product (A) is ________ \( \text{g mol}^{-1} \).
(Given molar mass in \( \text{g mol}^{-1} \) of C : \( 12 \), H : \( 1 \), O : \( 16 \), Br : \( 80 \), N : \( 14 \), P : \( 31 \))

During "S" estimation, \( 160 \, \text{mg} \) of an organic compound gives \( 466 \, \text{mg} \) of barium sulphate. The percentage of Sulphur in the given compound is ________ \( \% \).
(Given molar mass in \( \text{g mol}^{-1} \) of Ba : \( 137 \), S : \( 32 \), O : \( 16 \))

For the thermal decomposition of \( \mathrm{N_2O_5} \, (g) \) at constant volume, the following table can be formed, for the reaction mentioned below.
\( 2\mathrm{N_2O_5}(g) \rightarrow 2\mathrm{N_2O_4}(g) + \mathrm{O_2}(g) \)

\( x = \) ________ \( \times 10^{-3} \) atm [nearest integer]
Given: Rate constant for the reaction is \( 4.606 \times 10^{-2} \, \text{s}^{-1} \).

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

JEE Main 2025 23rd Jan Morning Shift

Mathematics Physics Chemistry

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The major product of the following reaction is: \( \mathrm{CH_3CH_2CH{=}O} \xrightarrow[\text{reflux}]{\text{excess } \mathrm{HCHO}\ \text{alkali}} \ ? \)