List of top Chemistry Questions asked in JEE Main

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

In acidic medium, \( K_2Cr_2O_7 \) shows oxidizing action as represented in the half-reaction: \(Cr_2O_7^{2-} + XH^+ + Ye^- \rightarrow 2A + ZH_2O\)
\( X \), \( Y \), \( Z \), and \( A \) are respectively:

Arrange the bonds in order of increasing ionic character in the molecules. LiF, K\(_2\)O, N\(_2\), SO\(_2\), and ClF\(_3\).

According to the wave-particle duality of matter by de-Broglie, which of the following graph plot presents most appropriate relationship between wavelength of electron () and momentum of electron (p)?

In Kjeldahl’s method for estimation of nitrogen, CuSO\(_4\) acts as:

Ionic reactions with organic compounds proceed through:
(A) Homolytic bond cleavage
(B) Heterolytic bond cleavage
(C) Free radical formation
(D) Primary free radical
(E) Secondary free radical
Choose the correct answer from the options given below:

Identify A and B in the following sequence of reaction.

We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentration 0.1 M, 0.01M & 0.001 M, respectively. The value of vant’ Haft factor (i) for these solutions will be in the order.

Number of geometrical isomers possible for the given structure is/are ___________.

NaCl reacts with conc. \( H_2SO_4 \) and \( K_2Cr_2O_7 \) to give reddish fumes (B), which react with NaOH to give yellow solution (C). (B) and (C) respectively are:

The total number of correct statements, regarding the nucleic acids is_________.
A. RNA is regarded as the reserve of genetic information.
B. DNA molecule self-duplicates during cell division.
C. DNA synthesizes proteins in the cell.
D. The message for the synthesis of particular proteins is present in DNA.
E. Identical DNA strands are transferred to daughter cells.

$\text{2-chlorobutane} + \text{Cl}_2 \rightarrow \text{C}_4\text{H}_8\text{Cl}_2 \, (\text{isomers})$
$\text{Total number of optically active isomers shown by} \, \text{C}_4\text{H}_8\text{Cl}_2, \, \text{obtained in the above reaction is} \, \_\_\_\_\_\_.$

Sum of bond order of CO and NO⁺ is _____.

Number of spectral lines obtained in He⁺ spectra, when an electron makes transition from fifth excited state to first excited state will be __________.

Which of the following electronic configurations would be associated with the highest magnetic moment?

Mass of methane required to produce 22 g of CO₂​ after complete combustion is ______ g.
(Given Molar mass in g mol⁻¹: C=12.0, H=1.0, O=16.0).

Among the following, total number of meta directing functional groups is (Integer based) \(−OCH_3​, −NO_2​, −CN, −CH_3​, −NHCOCH_3​, −COR, −OH, −COOH, −Cl\).

The number of electrons present in all the completely filled subshells having n=4 and s=+½​ is _____. (Where n = principal quantum number and s = spin quantum number).

Given below are two statements:
Statement (I): Aqueous solution of ammonium carbonate is basic.
Statement (II): Acidic/basic nature of salt solution of a salt of weak acid and weak base depends on \( K_a \) and \( K_b \) value of acid and the base forming it.
In the light of the above statements, choose the most appropriate answer from the options given below:

3-Methylhex-2-ene on reaction with HBr in presence of peroxide forms an addition product (A). The number of possible stereoisomers for 'A' is ______.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Melting point of Boron (2453 K) is unusually high in group 13 elements.
Reason (R): Solid Boron has a very strong crystalline lattice. 
In the light of the above statements, choose the most appropriate answer from the options given below:

$\text{Two reactions are given below:}$ \[ 2\text{Fe}_{(s)} + \frac{3}{2}\text{O}_{2(g)} \rightarrow \text{Fe}_2\text{O}_{3(s)}, \Delta H^\circ = -822 \, \text{kJ/mol} \] \[ \text{C}_{(s)} + \frac{1}{2}\text{O}_{2(g)} \rightarrow \text{CO}_{(g)}, \Delta H^\circ = -110 \, \text{kJ/mol} \] $\text{Then enthalpy change for the following reaction}$ \[ 3\text{C}_{(s)} + \text{Fe}_2\text{O}_{3(s)} \rightarrow 2\text{Fe}_{(s)} + 3\text{CO}_{(g)} \]

The mass of silver (Molar mass of Ag : 108 gmol^–1 ) displaced by a quantity of electricity which displaces 5600 mL of O₂ at S.T.P. will be _____ g.

The correct statement regarding nucleophilic substitution reaction in a chiral alkyl halide is: