List of top Chemistry Questions asked in JEE Main

Freezing point of solution is less than that of pure solvent, which of the following statements are correct ? 
(A) Vapour pressure of solution is less than that of pure solvent 
(B) Vapour pressure of solution is greater than that of pure solvent 
(C) Only solvent molecules will freeze 
(D) Only solute molecules will freeze

Which of the following complex will show largest splitting of $d$-orbitals?

\(A(g) ⇋ 2B(g) + C(g)\)
For the given reaction, if the initial pressure is 450 mm Hg and the pressure at time t is 720 mm Hg at a constant temperature T and constant volume V. The fraction of A(g) decomposed under these conditions is \(x × 10^{–1}\). The value of x is _____ . (nearest integer)

In alkaline medium, the reduction of permanganate anion involves a gain of _____ electrons.

The electron in the \(n^{th}\) orbit of \(Li^{2+}\) is excited to \((n + 1)\) orbit using the radiation of energy \(1.47 × 10^{–1}J \) (as shown in the diagrarn). The value of n is ______ .
Given: \(R_H = 2.18 × 10^{–18} J\).

The number of incorrect statement/s from the following is ____ .
A. The successive half lives of zero order reactions decreases with time.
B. A substance appearing as reactant in the chemical equation may not affect the rate of reaction.
C. Order and molecularity of a chemical reaction can be a fractional number.
D. The rate constant units of zero and second order reaction are mol L^–1s^–1 and mol^–1 Ls^–1 respectively.

During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of 3. Identify which of the below medium will favour the reaction

The number of endothermic process/es from the following is _____ .
A. \(I_2 (g) → 2I (g)\)
B. \(HCl (g) → H(g) + Cl (g)\)
C. \(H_2O(l) → H_2O (g)\)
D. \(C(s) + O_2 (g) → CO_2 (g)\)
E. Dissolution of ammonium chloride in water.

The difference in the oxidation state of \(Xe\) between the oxidised product of \(Xe\) formed on complete hydrolysis of \(XeF_4\) and \(XeF_4\) is _____ .

An aqueous solution of volume 300 cm³ contains 0.63 g of protein. The osmotic pressure of the solution
at 300 K is 1.29 mbar. The molar mass of the protein is ____ g mol^–1.
Given: R = 0.083 L bar K^–1 mol^–1

The specific conductance of 0.0025 M acetic acid is \(5 × 10^{–5} S\ cm^{–1}\) at a certain temperature. The dissociation constant of acetic acid is ___________ \(× 10^{–7}.\) (Nearest integer) Consider limiting molar conductivity of \(CH_3COOH\) as \(400\  S cm^2 mol^{–1}\).

The number of molecules from the following which contain only two lone pair of electrons is _____ .
\(H_2O, N_2, CO, XeF_4, NH_3, NO, CO_2, F_2\)

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: 3.1500 g of hydrated oxalic acid dissolved in water to make 250.0 mL solution will result in 0.1 M oxalic acid solution.
Reason R: Molar mass of hydrated oxalic acid is 126 g mol^–1.
In the light of the above statements, choose the correct answer from the options given below.

Which one of the following elements will remain as liquid inside pure boiling water?

Ferric chloride is applied to stop bleeding because-

The major product P formed in the given reaction is:

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: The energy required to form \(Mg^{2+}\) from Mg is much higher than that required to produce \(Mg^+\)
Reason R: \(Mg^{2+}\) is small ion and carry more charge than \(Mg^{+}\).
In the light of the above statements, choose the correct answer from the options given below.

Incorrect method of preparation for alcohols from the following is:

The decreasing order of hydride affinity for following carbocations is:
Choose the correct answer from the options given below:

The correct order of the number of unpaired electrons in the given complexes is
A. \([Fe(CN)_6]^{3–}\)
B. \([FeF_6]^{3–}\)
C. \([CoF_6]^{3–}\)
D. \([Cr(oxalate)_3]^{3–}\)
E. \([Ni(CO)_4]\)
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: Physical properties of isotopes of hydrogen are different.
Reason R: Mass difference between isotopes of hydrogen is very large.
In the light of the above statements, choose the correct answer from the options given below:

Buna-S can be represented as:

Gibbs energy vs T plot for the formation of oxides is given below.

For the given diagram, the correct statement is -