List of top Chemistry Questions asked in JEE Main

Two nucleotides are joined together by a linkage known as:

The number of species from the following which are paramagnetic and with bond order equal to one is ___.
Species: H₂, He₂⁺, O₂^-, N₂, O₂^2-, F₂, Ne₂⁺, B₂

For a reaction taking place in three steps at the same temperature, the overall rate constant \( K = \frac{K_1 K_2}{K_3} \). If \( E_{a1} \), \( E_{a2} \), and \( E_{a3} \) are 40, 50, and 60 kJ/mol respectively, the overall \( E_a \) is ____ kJ/mol.

For a reaction taking place in three steps at the same temperature, the overall rate constant \( K = \frac{K_1 K_2}{K_3} \). If \( E_{a1} \), \( E_{a2} \), and \( E_{a3} \) are 40, 50, and 60 kJ/mol respectively, the overall \( E_a \) is ____ kJ/mol.

Consider the given reaction. The total number of oxygen atoms present per molecule of the product (P) is____.

From the compounds given below, the number of compounds which give a positive Fehling’s test is____.
Compounds: Benzaldehyde, Acetaldehyde, Acetone, Acetophenone, Methanal, 4-nitrobenzaldehyde, cyclohexane carbaldehyde.

The number of species from the following which are paramagnetic and with bond order equal to one is ___.

Species: H₂, He₂⁺, O₂^-, N₂, O₂^2-, F₂, Ne₂⁺, B₂

Number of compounds among the following which contain sulfur as a heteroatom is ___.
Compounds: Furan, Thiophene, Pyridine, Pyrrole, Cysteine, Tyrosine

The osmotic pressure of a dilute solution is \(7 × 10^5\) Pa at \(273K\). Osmotic pressure of the same solution at\(283K\) is _____\(× 10^4 Nm^2\)

A solution of \( \text{H}_2\text{SO}_4 \) is 31.4% \( \text{H}_2\text{SO}_4 \) by mass and has a density of \( 1.25 \, \text{g/mL} \). The molarity of the \( \text{H}_2\text{SO}_4 \) solution is _____ M (nearest integer).
[Given molar mass of \( \text{H}_2\text{SO}_4 = 98 \, \text{g/mol} \)]

For the reaction \( \text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g) \), \( K_p = 0.492 \, \text{atm} \) at 300 K. \( K_c \) for the reaction at the same temperature is _____ \( \times \, 10^{-2} \).
(Given: \( R = 0.082 \, \text{L atm mol}^{-1} \text{K}^{-1} \))

The mass of sodium acetate (CH₃COONa) required to prepare 250 mL of 0.35 M aqueous solution is g. (Molar mass of CH₃COONa is 82.02 g/mol)

The mass of zinc produced by the electrolysis of zinc sulfate solution with a steady current of 0.015 A for 15 minutes is _____ \( \times \, 10^{-4} \) g.
(Atomic mass of zinc = 65.4 amu)

The total number of molecular orbitals formed from 2s and 2p atomic orbitals of a diatomic molecule is _________.

Number of compounds with one lone pair of electrons on central atom amongst following is
\(CIF_3, XeO_3, BrF_5, XeF_4, O_3, NH_3\),\( H_2O\)

Compound A formed in the following reaction reacts with B gives the product C. Find out A and B.\[ \text{CH}_3 - \text{C} \equiv \text{CH} + \text{Na} \xrightarrow{} \text{A}\xrightarrow{B} \text{CH}_3 - \text{C} \equiv \text{C} - \text{CH}_2 - \text{CH}_2 + \text{NaBr}(C)\]

In alkaline medium, \( \text{MnO}_4^- \) oxidizes \( \text{I}^- \) to:

Chlorine undergoes disproportionation in alkaline medium as shown below:
\(a \, \text{Cl}_2(g) + b \, \text{OH}^-(\text{aq}) \rightarrow c \, \text{ClO}^-(\text{aq}) + d \, \text{Cl}^-(\text{aq}) + e \, \text{H}_2\text{O}(\text{l})\)
The values of \( a \), \( b \), \( c \), and \( d \) in a balanced redox reaction are respectively:

Sugar which does not give reddish brown precipitate with Fehling‟s reagent is:

The final product A formed in the following multistep reaction sequence is

In which one of the following metal carbonyls, CO forms a bridge between metal atoms?

KMnO₄ decomposes on heating at 513 K to form O₂ along with