List of top Chemistry Questions asked in JEE Main

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 \(40 \, \text{g/mol}\)

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: \(R = 0.082 \, \text{L atm K}^{-1} \text{mol}^{-1}\)

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:

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:

Which of the following material is not a semiconductor.

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 :

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 :

Identify the incorrect statements about group 15 elements:
(A) Dinitrogen is a diatomic gas which acts like an inert gas at room temperature.
(B) The common oxidation states of these elements are −3, +3 and +5.
(C) Nitrogen has unique ability to form p$\pi$-p$\pi$ multiple bonds.
(D) The stability of +5 oxidation states increases down the group.
(E) Nitrogen shows a maximum covalency of 6.
Choose the correct answer from the options given below.

Match List-I with List-II.

List-I (Test)	List-II (Identification)
(A) Bayer's test	(I) Phenol
(B) Ceric ammonium nitrate test	(II) Aldehyde
(C) Phthalein dye test	(III) Alcoholic-OH group
(D) Schiff's test	(IV) Unsaturation

Choose the correct answer from the options given below:

The shape of carbocation is :

Given below are two statements:
Statement (I) : S$_N$2 reactions are 'stereospecific', indicating that they result in the formation only one stereo-isomers as the product.
Statement (II) : S$_N$1 reactions generally result in formation of product as racemic mixtures.
In the light of the above statements, choose the correct answer from the options given below :

Match List-I with List-II.

Choose the correct answer from the options given below :

Which one the following compounds will readily react with dilute NaOH?

When $\psi_A$ and $\psi_B$ are the wave functions of atomic orbitals, then $\sigma^*$ is represented by :

In qualitative test for identification of presence of phosphorous, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :

For a reaction $A \xrightarrow{K_1} B \xrightarrow{K_2} C$ If the rate of formation of B is set to be zero then the concentration of B is given by:

Number of ambidentate ligands among the following is ____.
\[ \text{NO}_2^{-}, \text{SCN}^{-}, \text{C}_2\text{O}_4^{2-}, \text{NH}_3, \text{CN}^{-}, \text{SO}_4^{2-}, \text{H}_2\text{O} \]

How many compounds among the following compounds show inductive, mesomeric as well as hyperconjugation effects?

The total number of species from the following in which one unpaired electron is present, is ____.
\[ \text{N}_2, \text{O}_2, \text{C}_2^{-}, \text{O}_2^{-}, \text{H}_2^{+}, \text{CN}^{-}, \text{He}_2^{+} \]

Total number of essential amino acid among the given list of amino acids is _______.
Arginine, Phenylalanine, Aspartic acid, Cysteine, Histidine, Valine, Proline