List of top Chemistry Questions asked in JEE Main

The complex of \( Ni^{2+}\) ion and dimethyl glyoxime contains \(\_\_\_\_\_\) number of Hydrogen (H) atoms. 
Consider the following cases of standard enthalpy of reaction (\( \Delta H_f^\circ \) in kJ mol\(^{-1}\)): \[ \text{C}_2\text{H}_6(g) + 7 \text{O}_2(g) \rightarrow 2 \text{CO}_2(g) + 3 \text{H}_2\text{O}(l) \quad \Delta H_1^\circ = -1550 \] \[ \text{C(graphite)} + \text{O}_2(g) \rightarrow \text{CO}_2(g) \quad \Delta H_2^\circ = -393.5 \] \[ \text{H}_2(g) + \frac{1}{2} \text{O}_2(g) \rightarrow \text{H}_2\text{O}(g) \quad \Delta H_3^\circ = -286 \] The magnitude of \( \Delta H_f^\circ \) of \( \text{C}_2\text{H}_6(g) \) is \(\_\_\_\_\_\) kJ mol\(^{-1}\) (Nearest integer). 
The compound with molecular formula C\(_6\)H\(_6\), which gives only one monobromo derivative and takes up four moles of hydrogen per mole for complete hydrogenation has \(\_\_\_\_\_\)\( \pi \) electrons. 
Niobium (Nb) and ruthenium (Ru) have "x" and "y" number of electrons in their respective 4d orbitals. The value of \( x + y \) is: 
The maximum covalency of a non-metallic group 15 element 'E' with the weakest E-E bond is:
The correct order of the following complexes in terms of their crystal field stabilization energies is:

Given below are two statements: 
Statement (I): An element in the extreme left of the periodic table forms acidic oxides.
Statement (II): Acid is formed during the reaction between water and oxide of a reactive element present in the extreme right of the periodic table.

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

Arrange the following compounds in increasing order of their dipole moment:
HBr, H\(_2\)S, NF\(_3\), and CCl\(_3\)
The alkane from below having two secondary hydrogens is:
Given below are two statements: 
Statement (I): A spectral line will be observed for a 2p\(_x\) \(\rightarrow\) 2p\(_y\) transition.
Statement (II): 2p\(_x\) and 2p\(_y\) are degenerate orbitals.
In the light of the above statements, choose the correct answer from the options given below:
The maximum number of RBr producing 2-methylbutane by above sequence is _____________.
RBr 2 methylbutane
The molar solubility(s) of zirconium phosphate with molecular formula \( \text{Zr}^{4+} \text{PO}_4^{3-} \) is given by relation:
Match the Compounds (List- I) with the appropriate Catalyst/Reagents (List- II) for their reduction into corresponding amines.
Match the Compounds (List- I) with the appropriate Catalyst/Reagents (List- II) for their reduction into corresponding amines.
The most stable carbocation from the following is:

A group 15 element forms \( d\pi - d\pi \) bond with transition metals. It also forms a hydride, which is the strongest base among the hydrides of other group members that form \( d\pi - d\pi \) bonds. The atomic number of the element is …….

Total number of molecules/species from the following which will be paramagnetic is ………. \[ O_2, O_2^+, O_2^-, NO, NO_2, CO, K_2[NiCl_4], [Co(NH_3)_6]Cl_3, K_2[Ni(CN)_4] \]

Consider the following data: 
- Heat of formation of \( CO_2(g) \) = -393.5 kJ mol\(^{-1}\) 
- Heat of formation of \( H_2O(l) \) = -286.0 kJ mol\(^{-1}\) 
- Heat of combustion of benzene = -3267.0 kJ mol\(^{-1}\) 
The heat of formation of benzene is ……… kJ mol\(^{-1}\) (Nearest integer).

The spin-only magnetic moment (\(\mu\)) value (B.M.) of the compound with the strongest oxidising power among \(Mn_2O_3\), \(TiO\), and \(VO\) is ……. B.M. (Nearest integer).

Which of the following is/are correct with respect to the energy of atomic orbitals of a hydrogen atom? 
(A) \( 1s<2s<2p<3d<4s \) 
(B) \( 1s<2s = 2p<3s = 3p \) 
(C) \( 1s<2s<2p<3s<3p \) 
(D) \( 1s<2s<4s<3d \) 
Choose the correct answer from the options given below:

Match List - I with List - II. 
         List - I (Saccharides)     List - II (Glycosidic linkages found) 
         (A) Sucrose                     (I) \( \alpha 1 - 4 \)
         (B) Maltose                    (II) \( \alpha 1 - 4 \) and \( \alpha 1 - 6 \)
         (C) Lactose                     (III) \( \alpha 1 - \beta 2 \)
         (D) Amylopectin            (IV) \( \beta 1 - 4 \)

Choose the correct answer from the options given below:

An ideal gas undergoes a cyclic transformation starting from point A and coming back to the same point by tracing the path A→B→C→D→A as shown in the three cases below.



Choose the correct option regarding \(\Delta U\):

Identify correct conversion during acidic hydrolysis from the following: 
(A) Starch gives galactose. 
(B) Cane sugar gives equal amount of glucose and fructose. 
(C) Milk sugar gives glucose and galactose. 
(D) Amylopectin gives glucose and fructose. 
(E) Amylose gives only glucose. 
Choose the correct answer from the options given below:

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 \( k = \sqrt{\frac{k_1 k_3}{k_2}} \). If the activation energies of the three steps are 60, 30, and 10 kJ mol\(^{-1}\) respectively, then the overall energy of activation in kJ mol\(^{-1}\) is \(\_\_\_\_\)(Nearest integer).

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

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