List of top Chemistry Questions asked in JEE Main

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. 
Assertion A : \(LiF\) is sparingly soluble in water.
Reason R : The ionic radius of \(Li^+\) ion is smallest among its group members, hence has least hydration enthalpy.
In the light of the above statements, choose the most appropriate answer from the options given below.

Which statement is not true with respect to nitrate ion test?

Given below are two statements:
Statement I : According to the Ellingham diagram, any metal oxide with higher ΔG° is more stable than the one with lower ΔG°.
Statement II :The metal involved in the formation of oxide placed lower in the Ellingham diagram can reduce the oxide of a metal placed higher in the diagram.
In the light of the above statements, choose the most appropriate answer from the options given below

The molar heat capacity for an ideal gas at constant pressure is 20.785 J K^–1 mol^–1. The change in internal energy is 5000 J upon heating it from 300 K to 500 K. The number of moles of the gas at constant volume is _____. (Nearest integer)
(Given : R = 8.314 JK-1mol-1).

Among the following ores Bauxite, Siderite, Cuprite, Calamine, Haematite, Kaolinite, Malachite, Magnetite, Sphalerite, Limonite, Cryolite, the number of principal ores of iron is____.

Number of lone pair(s) of electrons on central atom and the shape of BrF₃ molecule respectively, are

The hybridization of P exhibited in \(PF_5\) is \(sp_xd_y\). The value of y is _____ .

The product formed in the following reaction.

\(\dot Cl + CH_4 → A + B\)
A and B in the above atmospheric reaction step are:

During halogen test, sodium fusion extract is boiled with concentrated HNO₃ to

Haemoglobin contains \(0.34\%\) of iron by mass. The number of Fe atoms in \(3.3\) g of haemoglobin is(Given: Atomic mass of Fe is \(56\) u, \(N_A\) = \(6.022 × 1023\) \(mol^{–1}\))

Given below are two statements: one is labelled as Assertion A and other is labelled as Reason R.
Assertion A : Finest gold is red in colour, as the size of the particles increases, it appears purple then blue and finally gold.
Reason R : The colour of the colloidal solution depends on the wavelength of light scattered by the dispersed particles.
In the light of the above statements, choose the most appropriate answer from the options given below.

An organic compound ‘A’ contains nitrogen and chlorine. It dissolves readily in water to give a solution that turns litmus red. Titration of compound ‘A’ with standard base indicates that the molecular weight of ‘A’ IS 131±2. When a sample of ‘A’ is treated with aq. NaOH, a liquid separates which contains N but not Cl. Treatment of the obtained liquid with nitrous acid followed by phenol gives orange precipitate. The compound A is :

\(2\ g\) of a non-volatile non-electrolyte solute is dissolved in \(200\ g\) of two different solvents A and B whose ebullioscopic constants are in the ratio of \(1:8\). The elevation in boiling points of A and B are in the ratio \(\frac xy\ (x : y)\). The value of \(y\) is ______ . (Nearest Integer)

The standard entropy change for the reaction \(4Fe(s) + 3O_2(g) → 2Fe_2O_3(s)\) is \(–550\ J K^{–1}\) at \(298\ K\). The temperature in K at which the reaction attains equilibrium is ______. (Nearest Integer)
[Given: The standard enthalpy change for the reaction is \(–165\ kJmol^{–1}\)].

Metal deficiency defect is shown by \(Fe_{0.93}O\). In the crystal, some \(Fe^{2+}\) cations are missing and loss of positive charge is compensated by the presence of \(Fe^{3+}\) ions. The percentage of \(Fe^{2+}\) ions in the \(Fe_{0.93}O\) crystals is ______ . (Nearest integer)

The dark purple colour of \(KMnO_4\) disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is :

Which one of the following is a reducing sugar?

The number of oxygens present in a nucleotide formed from a base, that is present only in RNA is ________.

Which one of the following is NOT a copolymer?

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Experimental reaction of \(CH_3Cl\) with aniline and anhydrous \(AlCl_3\) does not give o and p-methylaniline.
Reason (R): The \(–NH_2\)group of aniline becomes deactivating because of salt formation with anhydrous \(AlCl_3\) and hence yields m-methyl aniline as the product.
In the light of the above statements, choose the most appropriate answer from the options given below :