List of top Chemistry Questions asked in JEE Main

When \( \text{MnO}_2 \) and \( \text{H}_2\text{SO}_4 \) is added to a salt (A), the greenish yellow gas liberated as salt (A) is:

Fuel cell, using hydrogen and oxygen as fuels,
A. has been used in spaceship
B. has as efficiency of 40% to produce electricity
C. uses aluminium as catalysts
D. is eco-friendly
E. is actually a type of Galvanic cell only

Product P is

Common name of Benzene-1, 2-diol is

The number of species from the following that have pyramidal geometry around the central atom is ______
\( \text{S}_2\text{O}_3^{2-}, \, \text{SO}_4^{2-}, \, \text{SO}_3^{2-}, \, \text{S}_2\text{O}_7^{2-} \)

The number of unpaired d-electrons in \([ \text{Co}(\text{H}_2\text{O})_6 ]^{3+}\) is ______

Correct order of stability of carbanion is

Consider the following reaction, the rate expression of which is given below:
\( \text{A} + \text{B} \to \text{C} \)
\(\text{rate} = k [\text{A}]^{1/2} [\text{B}]^{1/2}\)
The reaction is initiated by taking 1M concentration of A and B each. If the rate constant (\(k\)) is \(4.6 \times 10^{-2} \, \text{s}^{-1}\), then the time taken for A to become 0.1 M is ______ sec. (nearest integer)

For a strong electrolyte, a plot of molar conductivity against \( (\text{concentration})^{1/2} \) is a straight line, with a negative slope, the correct unit for the slope is:

Given below are two statements:
Statement I: The correct order of first ionization enthalpy values of Li, Na, F, and Cl is \( \text{Na} < \text{Li} < \text{Cl} < \text{F} \).
Statement II: The correct order of negative electron gain enthalpy values of Li, Na, F, and Cl is \( \text{Na} < \text{Li} < \text{F} < \text{Cl} \).
In the light of the above statements, choose the correct answer from the options given below:

Consider the above reactions, identify product B and product C.

Phthalimide is made to undergo following sequence of reactions.

Total number of \( \pi \) bonds present in product 'P' is/are ______

A first row transition metal in its +2 oxidation state has a spin-only magnetic moment value of 3.86 BM. The atomic number of the metal is

The correct statement/s about Hydrogen bonding is/are :
A. Hydrogen bonding exists when H is covalently bonded to the highly electro negative atom.
B. Intermolecular H bonding is present in o-nitro phenol
C. Intramolecular H bonding is present in HF.
D. The magnitude of H bonding depends on the physical state of the compound.
E. H-bonding has powerful effect on the structure and properties of compounds.
Choose the correct answer from the options given below :

For the electrochemical cell
M|M$^{2+}$||X$^{2-}$|X
If $E^0_{(M^{2+}/M)} = 0.46$ V and $E^0_{(X/X^{2-})} = 0.34$ V.
Which of the following is correct?

The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is _______. Ti²⁺, Cr²⁺ and V²⁺.

While preparing crystals of Mohr's salt, dil. \(H_2SO_4\) is added to a mixture of ferrous sulphate and ammonium sulphate, before dissolving this mixture in water, dil. \(H_2SO_4\) is added here to:

Match List - I with List - II.

List - I (Pair of Compounds)	List - II (Isomerism)
(A) n-propanol and Isopropanol	(I) Metamerism
(B) Methoxypropane and ethoxyethane	(IV) Functional Isomerism
(C) Propanone and propanal	(III) Position Isomerism
(D) Neopentane and Isopentane	(II) Chain Isomerism

Given below are two statements:
Statement I: On passing HCl$_{(g)}$ through a saturated solution of BaCl$_2$, at room temperature white turbidity appears.
Statement II: When HCl gas is passed through a saturated solution of NaCl, sodium chloride is precipitated due to common ion effect.
In the light of the above statements, choose the most appropriate answer from the options given below:

The number of complexes from the following with no electrons in the t$_{2g}$ orbital is _______.
TiCl$_4$, [MnO$_4$]$^{-}$, [FeO$_4$]$^{2-}$, [FeCl$_4$]$^{-}$, [CoCl$_4$]$^{2-}$

The number of moles of methane required to produce 11g \(CO_2\) (g) after complete combustion is:
(Given molar mass of methane in g mol^–1 : 16)

The total number of 'sigma' and 'Pi' bonds in 2-oxohex-4-ynoic acid is____.

Match List - I with List - II.

List - I	List - II
(A) ICl	(IV) Linear
(B) ICl3	(I) T-Shape
(C) ClF5	(II) Square pyramidal
(D) IF7	(III) Pentagonal bipyramidal

Choose the correct 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): NH$_3$ and NF$_3$ molecule have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of NH$_3$ is greater than that of NF$_3$.
Reason (R): In NH$_3$, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the N$-$H bonds. F is the most electronegative element.
In the light of the above statements, choose the correct answer from the options given below:

Given below are two statements:
Statement I: The metallic radius of Na is 1.86 Å and the ionic radius of Na$^+$ is lesser than 1.86 Å.
Statement II: Ions are always smaller in size than the corresponding elements.
In the light of the above statements, choose the correct answer from the options given below: