List of top Chemistry Questions asked in JEE Main

Which one of the following reaction sequences will give an azo dye?
Which among the following halides will generate the most stable carbocation in a nucleophilic substitution reaction?
First ionisation enthalpy values of the first four group 15 elements are given below. Choose the correct value for the element that is a main component of the apatite family:
The type of oxide formed by the element among Li, Na, Be, Mg, B and Al that has the least atomic radius is:
Given below are two statements:
Statement (I): It is impossible to specify simultaneously with arbitrary precision, the linear momentum and the position of a particle.
Statement (II): If the uncertainty in the measurement of position and uncertainty in measurement of momentum are equal for an electron, then the uncertainty in the measurement of velocity is \( \geq \sqrt{\frac{h}{\pi}} \times \frac{1}{2m} \).
In the light of the above statements, choose the correct answer from the options given below:
Total number of sigma (\( \sigma \)) and pi (\( \pi \)) bonds respectively present in hex-1-en-4-yne are:
Given below are two statements:
Statement (I): On nitration of m-xylene with \( \text{HNO}_3 \), \( \text{H}_2\text{SO}_4 \), followed by oxidation, 4-nitrobenzene-1, 3-dicarboxylic acid is obtained as the major product.
Statement (II): CH\(_3\) group is o/p-directing while NO\(_2\) group is m-directing group.
In the light of the above statements, choose the correct answer from the options given below:
0.1 M solution of KI reacts with excess of \( \text{H}_2\text{SO}_4 \) and KIO\(_3\), according to the equation: \[ 5I^- + 6H^+ \rightarrow 3I_2 + 3H_2O \] Identify the correct statements:
In the Claisen-Schmidt reaction to prepare dibenzalacetone from 5.3 g benzaldehyde, a total of 3.51 g of product was obtained. The percentage yield in this reaction was _____.
The calculated spin-only magnetic moments of \( K_3[Fe(OH)_6] \) and \( K_4[Fe(OH)_6] \) respectively are:
If \[ \text{C(diamond)} \rightarrow \text{C(graphite)} + X \, \text{kj mol}^{-1} \] \[ \text{C(diamond)} + \text{O}_2(g) \rightarrow \text{CO}(g) + Y \, \text{kj mol}^{-1} \] \[ \text{C(graphite)} + \text{O}_2(g) \rightarrow \text{CO}(g) + Z \, \text{kj mol}^{-1} \] At constant temperature. Then:
Statement – 1: First ionization energy of Ge is greater than Si.
Statement – 2: First ionization energy of Pb is greater than Sn.
The heat of formation of \( \text{SO}_2(g) \) is given by: \[ S(g) + \frac{3}{2} O_2(g) \rightarrow SO_3(g) + 2x \, \text{kcal} \] \[ SO_2(g) + \frac{1}{2} O_2(g) \rightarrow SO_3(g) + y \, \text{kcal} \]
The reaction \( {A}_2 + {B}_2 \to 2{AB} \) follows the mechanism: \[ {A}_2 \xrightarrow{k_1} {A} + {A} \ ({fast}) \quad {A} + {B}_2 \xrightarrow{k_2} {AB} + {B} \ ({slow}) \quad {A} + {B} \to {AB} \ ({fast}) \] The overall order of the reaction is:
Match List - I with List - II.

\[ \begin{array}{|c|c|} \hline \text{List - I} & \text{List - II} \\ \hline \text{(A) } \text{Ti}^{3+} & \text{(I) } 3.87 \\ \text{(B) } \text{V}^{2+} & \text{(II) } 0.00 \\ \text{(C) } \text{Ni}^{2+} & \text{(III) } 1.73 \\ \text{(D) } \text{Sc}^{3+} & \text{(IV) } 2.84 \\ \hline \end{array} \]

The conditions and consequences that favour the \( t_{2g}^3 e_g^1 \) configuration in a metal complex are:
Choose the correct statements.
(A) Weight of a substance is the amount of matter present in it.
(B) Mass is the force exerted by gravity on an object.
(C) Volume is the amount of space occupied by a substance.
(D) Temperatures below \(0^\circ\)C are possible in Celsius scale, but in Kelvin scale negative temperature is not possible.
(E) Precision refers to the closeness of various measurements for the same quantity.
Choose the correct answer from the options given below:
Match List - I with List - II: List - I: (A) Amylase
(B) Cellulose
(C) Glycogen
(D) Amylopectin
List - II: (I) \( \beta \)-C1-C4 plant
(II) \( \alpha \)-C1-C4 animal
(III) \( \alpha \)-C1-C4 \( \alpha \)-C1-C6 plant
(IV) \( \alpha \)-C1-C4 plant
Choose the correct answer from the options given below:
The correct option with order of melting points of the pairs (Mn, Fe), (Tc, Ru) and (Re, Os) is:

Given below are two statements: 
Statement I: Experimentally determined oxygen-oxygen bond lengths in the \( O_2 \) are found to be the same and the bond length is greater than that of a \( O=O \) (double bond) but less than that of a single \( O-O \) 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 \( O=O \) but more than that of a single bond \( O-O \). 
In light of the above statements, choose the correct answer from the options given below:

Find the compound \( A \) from the following reaction sequences: \[ A \xrightarrow{\text{aqua regia}} B \xrightarrow{(1) \, \text{KNO}_3, \, \text{NH}_4\text{OH}} \text{yellow ppt}. \]

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

In the given structure, number of \( sp \) and \( sp^2 \) hybridized carbon atoms present respectively are:

For hydrogen atom, the orbital/s with lowest energy is/are:
Which of the following mixing of 1M base and 1M acid leads to the largest increase in temperature?