List of top Chemistry Questions asked in JEE Main

In a borax bead test under hot condition, a metal salt (one from the given) is heated at point B of the flame, resulted in green colour salt bead. The spin-only magnetic moment value of the salt is ............. BM (Nearest integer)
[Given atomic number of Cu = 29, Ni = 28,Mn = 25, Fe = 26]
\(C_{11}H_{18}O_{12}\)The value of the Rydberg constant (\(R_H\)) is \(2.18 \times 10^{-18} \, \text{J}\). The velocity of an electron having mass \(9.1 \times 10^{-31} \, \text{kg}\) in Bohr's first orbit of the hydrogen atom is:\(\dots \times 10^5 \, \text{ms}^{-1}\) (nearest integer).
The number of neutrons present in the more abundant isotope of boron is 'x'. Amorphous boron upon heating with air forms a product, in which the oxidation state of boron is 'y'. The value of x + y is ...
Given below are two statements:
Statement I: Bromination of phenol in a solvent with low polarity such as CHCl\(_3\) or CS\(_2\) requires a Lewis acid catalyst.
Statement II: The Lewis acid catalyst polarizes the bromine to generate \( \text{Br}^+ \).
In light of the above statements, choose the correct answer from the options given below:
Ail organic compound has 42.1% carbon, 6.4% hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular formula is :
The metal that shows highest and maximum number of oxidation state is:
Which of the following gives a positive test with ninhydrin ?
The correct order of ligands arranged in increasing field strength.
Given below are two statements :
Statement I: Nitration of benzene involves the following step –
Reaction
Statement II: Use of Lewis base promotes the electrophilic substitution of benzene. In the light of the above statements.
Choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Cis form of alkene is found to be more polar than the trans form
Reason (R): Dipole moment of trans isomer of 2-butene is zero. In the light of the above statements.
Choose the correct answer from the options given below :
Which one of the following complexes will exhibit the least paramagnetic behaviour ? [Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27]
Given below are two statements :
Statement I: In group 13, the stability of +1 oxidation state increases down the group.
Statement II: The atomic size of gallium is greater than that of aluminium. In the light of the above statements.
Choose the most appropriate answer from the options given below:
For the compounds:
(A) \( \text{H}_3\text{C} - \text{CH}_2 - \text{O} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \)
(B) \( \text{H}_3\text{C} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \)  
(C) \( \text{CH}_3 - \text{CH}_2 - \text{C} - \text{CH}_2 - \text{CH}_3 \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\ \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\ \)  
(D) \( \text{H}_3\text{C} - \text{CH} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\ \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{OH}\ \)  
 
The increasing order of boiling point is: Choose the correct answer from the options given below:  
The statement(s) that are correct about the species O 2– , F – , Na+ and Mg2+.
(A) All are isoelectronic
(B) All have the same nuclear charge
(C) O2– has the largest ionic radii
(D) Mg2+ has the smallest ionic radii
Choose the most appropriate answer from the options given below :
The following reaction occurs in the Blast furnace where iron ore is reduced to iron metal:
\(\text{Fe}_2\text{O}_3(s) + 3\text{CO}(g) \rightleftharpoons 2\text{Fe}(l) + 3\text{CO}_2(g)\)
Using Le Chatelier's principle, predict which one of the following will not disturb the equilibrium.
The incorrect postulates of the Dalton's atomic theory are :
(A) Atoms of different elements differ in mass.
(B) Matter consists of divisible atoms.
(C) Compounds are formed when atoms of different element combine in a fixed ratio.
(D) All the atoms of given element have different properties including mass.
(E) Chemical reactions involve reorganisation of atoms.
Choose the correct answer from the options given below :
Number of molecules/species from the following having one unpaired electron is ________.
\( \text{O}_2, \, \text{O}_2^{1-}, \, \text{NO}, \, \text{CN}^{1-}, \, \text{O}_2^{2-} \)
The number of different chain isomers for \( \text{C}_7\text{H}_{16} \) is ______.
The de-Broglie's wavelength of an electron in the \( 4^{\text{th}} \) orbit is ______ \( \pi a_0 \). (\( a_0 = \text{Bohr's radius} \))
\( X \, \text{g} \) of ethylamine is subjected to reaction with \( \text{NaNO}_2/\text{HCl} \) followed by water; evolved dinitrogen gas which occupied \( 2.24 \, \text{L} \) volume at STP. \( X \) is ______ \( \times 10^{-1} \, \text{g} \).
The number of correct reaction(s) among the following is ________.
The correct order of first ionization enthalpy values of the following elements is :
(A) O (B) N (C) Be (D) F (E) B
Choose the correct answer from the options given below :
Identify the correct set of reagents or reaction conditions ‘X’ and ‘Y’ in the following set of transformation.
Identify the product in the following reaction :
The element which shows only one oxidation state other than its elemental form is :