List of top Chemistry Questions asked in JEE Main

The correct arrangement for decreasing order of electrophilic substitution for above compounds

In the Claisen-Schmidt reaction to prepare 351 g of dibenzalacetone using 87 g of acetone, the amount of benzaldehyde required is _________g. (Nearest integer)

Consider the following single step reaction in gas phase at constant temperature.
\(2A_{(g)} + B_{(g)} → C_{(g)}\)
The initial rate of the reaction is recorded as $r_1$ when the reaction starts with 1.5 atm pressure of A and 0.7 atm pressure of B. After some time, the rate $r_2$ is recorded when the pressure of C becomes 0.5 atm. The ratio $r_1 : r_2$ is _______ $\times 10^1$. (Nearest integer)

Number of compounds from the following with zero dipole moment is _______.
HF, H$_2$, H$_2$S, CO$_2$, NH$_3$, BF$_3$, CH$_4$, CHCl$_3$, SiF$_4$, H$_2$O, BeF$_2$

The product Ⓒ in the following sequence of reactions has _______ π bonds.

Using the given figure, the ratio of \(R_f\) values of sample A and sample C is x × 10^–2. Value of x is __________.

Considering acetic acid dissociates in water, its dissociation constant is $6.25 \times 10^{-5}$. If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at $-x \times 10^{-1}$ °C, provided pure water freezes at 0 °C. $x = $ _____ (Nearest integer)
Given: $(K_f)_{water} = 1.86$ K kg mol$^{-1}$
density of acetic acid is 1.2 g mol$^{-1}$
molar mass of water = 18 g mol$^{-1}$
molar mass of acetic acid = 60 g mol$^{-1}$
density of water = 1 g cm$^{-3}$
Acetic acid dissociates as CH$_3$COOH $\rightleftharpoons$ CH$_3$COO$^-$ + H$^+$

Identify A and B in the given chemical reaction sequence : -

Coagulation of egg, on heating is because of :

X of enthanamine was subjected to reaction with \(NaNO_2/HCl\) followed by hydrolysis to liberate \(N_2\) and HCl. The HCl generated was completely neutralised by 0.2 moles of NaOH. X is ____ g.

The correct statements from the following are:
(A) The decreasing order of atomic radii of group 13 elements is Tl $>$ In $>$ Ga $>$ Al $>$ B.
(B) Down the group 13 electronegativity decreases from top to bottom.
(C) Al dissolves in dil. HCl and liberate H$_2$, but conc. HNO$_3$ renders Al passive by forming a protective oxide layer on the surface.
(D) All elements of group 13 exhibits highly stable +1 oxidation state.
(E) Hybridisation of Al in [Al(H$_2$O)$_6$]$^{3+}$ ion is sp$^3$d$^2$.
Choose the correct answer from the options given below.

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products A and B along with the evolution of CO$_2$. The sum of spin-only magnetic moment values of A and B is ______ B.M. (Nearest integer)
(Given atomic number: C : 6, Na : 11, O : 8, Fe : 26, Cr : 24)

Combustion of 1 mole of benzene is expressed as C$_6$H$_6$(l) + $\frac{15}{2}$O$_2$(g) → 6CO$_2$(g) + 3H$_2$O(l). The standard enthalpy of combustion of 2 mol of benzene is x kJ. x = __________
(1) standard Enthalpy of formation of 1 mol of C$_6$H$_6$(l), for the reaction 6C(graphite) + 3H$_2$(g) → C$_6$H$_6$(l) is 48.5 kJ mol$^{-1}$.
(2) Standard Enthalpy of formation of 1 mol of \(CO_2\)(g),  for the reaction 6(graphite) + \(O_2(g)\) → CO$_2$(g) is -393.5 kJ mol$^{-1}$.
(3) Standard Enthalpy of formation of 1 mol of H$_2$O(l), for the reaction H$_2$(g) + $\frac{1}{2}$O$_2$(g) → H$_2$O(l) is -286 kJ mol$^{-1}$.

In an atom, total number of electrons having quantum numbers n = 4, $|m_l|$ = 1 and $m_s$ = $-\frac{1}{2}$ is ________.

Consider the given chemical reaction :

Product ''A'' is :

Consider the above reaction sequence and identify the major product P.

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

Which one of the following reactions is NOT possible?

The metal atom present in the complex MABXL (where A, B, X and L are unidentate ligands and M is metal) involves sp³ hybridization. The number of geometrical isomers exhibited by the complex is:

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

The quantity of silver deposited when one coulomb charge is passed through\(AgNO_3\)solution:

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:

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: