List of top Chemistry Questions asked in JEE Main

Match List - I with List - II.
Choose the correct answer from the options given below.
Given below are two statements:
Statement (I): A \(\pi\) bonding MO has lower electron density above and below the inter-nuclear axis.
Statement (II): The \(\pi^*\) antibonding MO has a node between the nuclei.
In the light of the above statements, choose the most appropriate answer from the options given below:
The transition metal having highest \(3^\text{rd}\) ionisation enthalpy is:
Among \(\text{CrO}\), \(\text{Cr}_2\text{O}_3\), and \(\text{CrO}_3\), the sum of spin-only magnetic moment values of basic and amphoteric oxides is ______ \( \times 10^{-2} \, \text{BM} \) (nearest integer).
Given: Atomic number of Cr is 24.
The major product of the following reaction is P.
Number of oxygen atoms present in product 'P' is _______ (nearest integer).
9.3 g of pure aniline upon diazotisation followed by coupling with phenol gives an orange dye. The mass of orange dye produced (assume 100% yield/ conversion) is ________g. (nearest integer)
Frequency of the de-Broglie wave of the electron in Bohr's first orbit of the hydrogen atom is ______ \( \times 10^{13} \, \text{Hz} \) (nearest integer).
Given:\(R_H\) (Rydberg constant) = \(2.18 \times 10^{-18} \, \text{J}\)\(h\) \((\)Planck's constant)= \(6.6 \times 10^{-34}\)\(\text{J.s}\)
Number of molecules from the following which can exhibit hydrogen bonding is ______. (nearest integer)
The difference in the 'spin-only' magnetic moment values of \( \text{KMnO}_4 \) and the manganese product formed during titration of \( \text{KMnO}_4 \) against oxalic acid in acidic medium is ______ BM (nearest integer).
Time required for 99.9% completion of a first order reaction is _____ time the time required for completion of 90% reaction.(nearest integer).
Consider the dissociation of the weak acid HX as given below:
\[\text{HX(aq)} \rightleftharpoons \text{H}^+(\text{aq}) + \text{X}^-(\text{aq}), \, K_a = 1.2 \times 10^{-5}\]
\([K_a: \text{dissociation constant}]\)
The osmotic pressure of \(0.03 \, \text{M}\) aqueous solution of HX at 300 K is ______ \( \times 10^{-2} \, \text{bar} \) (nearest integer).
Given: \(R = 0.083 \, \text{L bar mol}^{-1} \text{K}^{-1}\)
The electron affinity values are negative for:
A. Be → Be−
B. N → N−
C. O → O2−
D. Na → Na−
E. Al → Al−
Choose the most appropriate answer from the options given below:
Which among the following aldehydes is most reactive towards nucleophilic addition reactions?
Match List-I with the List-II
List-I
(Compound)		List-II
(Uses)
(A) Iodoform(I) Fire extinguisher
(B) Carbon
tetrachloride		(II) Insecticide
(C) CFC(III) Antiseptic
(D) DDT(IV) Refrigerants
Choose the correct answer from the options given below:
The number of element from the following that do not belong to lanthanoids is :
Eu, Cm, Er, Tb, Yb and Lu
At \(-20^\circ \text{C}\) and 1 atm pressure, a cylinder is filled with an equal number of \(H_2\), \(I_2\), and \(HI\) molecules for the reaction:
\[H_2(g) + I_2(g) \rightleftharpoons 2HI(g)\] The \(K_P\) for the process is \(x \times 10^{-1}\).
\(x = ___________)
Given: \(R = 0.082 \, \text{L atm K}^{-1} \text{mol}^{-1}\)
The density of 'x' M solution ('x' molar) of NaOH is \(1.12 \, \text{g/mL}\). While in molality, the concentration of the solution is \(3 \, \text{m}\) (3 molal). Then x is:
Given: Molar mass of NaOH is \(40 \, \text{g/mol}\)
Match List-I with the List-II
List-I
(Precipitating reagent and
conditions)		List-II
(Cation)
(A) \(NH_4Cl + NH_4OH\)(I) Mn2+
(B) \(NH_4OH + Na_2CO_3\)(II) Pb2+
(C) \(NH_4OH + NH_4Cl + H_2S gas\)(III) Al3+
(D) dilute HCl(IV) Sr2+
Choose the correct answer from the options given below:
Which of the following material is not a semiconductor.
Consider the following complexes:
\([CoCl(NH_3)_5]^{2+}\) (A)
\([Co(CN)_6]^{3-}\) (B)
\([Co(NH_3)_5(H_2O)]^{3+}\) (C)
\([Cu(H_2O)_4]^{2+}\) (D)
The correct order of A, B, C, and D in terms of wavenumber of light absorbed is:
The number of different chain isomers for \( \text{C}_7\text{H}_{16} \) is ______.
The equilibrium $\mathrm{Cr_2O_7^{2-}} \rightleftharpoons 2\mathrm{CrO_4^{2-}}$ is shifted to the right in:
IUPAC name of following hydrocarbon (X) is :
ch bond
Compare the energies of following sets of quantum numbers for multielectron system.
(A) n = 4, 1 = 1
(B) n= 4, l = 2
(C) n = 3, l = 1
(D) n = 3, l = 2
(E) n = 4, 1 = 0
Choose the correct answer from the options given below :
For the given compounds, the correct order of increasing \(pK_a\) value :
Chemical compounds