List of top Questions asked in JEE Main

30.4 kJ is required to melt one mole of sodium chloride. The entropy change during melting is 28.4 JK-1 mol-1 . atm The melting point of sodium chloride Calculate is ___ K(Nearest Integer).

Match list I with list II:

List I	Species	List II	Geometry/ Shape
A	H3 O+	I	Tetrahedral
B	Acetylide anion	II	Linera
C	NH4 +	III	Pyramidal
D	ClO2–	IV	Bent

Choose correct answer from the options given below:

During the borax bead test with CuSO₄, a blue-green colour of the bead was observed in oxidizing flame due to the formation of

Solid Lead nitrate is dissolved in 1 litre of water. The solution was found to boil at \(100.15\degree C\). When 0.2 mol of NaCl is added to the resulting solution, it was observed that the solution froze at \(–0.8\degree C\). The solubility product of PbCl₂ formed is ________ \(\times 10^{–6}\) at 298 K. (Nearest integer) Given: \(Kb = 0.5 K \text{ kg mol}^{–1}\) and \(Kf = 1.8 K \text{ kg mol}^{–1}\).
Assume molality to be equal to molarity in all cases.

If the boiling points of two solvents X and Y (having same molecular weights) are in the ratio 2:1 and their enthalpy of vaporizations are in the ratio 1:2, then the boiling point elevation constant of X is m times the boiling point elevation constant of Y. The value of m is ______ (nearest integer).

Lime reacts exothermally with water to give ‘A’ which has low solubility in water. Aqueous solution of ‘A’ is often used for the test of CO2 , a test in which insoluble B is formed. If B is further reacted with CO2 then soluble compound is formed ‘A’ is

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.

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 \(400\  S cm^2 mol^{–1}\).

Given below are two statements. one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : A solution of the product obtained by heating a mole of glycine with a mole of chlorine in presence of red phosphorous generates chiral carbon atom.
Reason R : A molecule with 2 chiral carbons is always optically active.
In the light of the above statements, choose the correct answer from the options given below:

What weight of glucose must be dissolved in 100 g of water to lower the vapour pressure by 0.20 mm Hg?
(Assume dilute solution is being formed)
Given : Vapour pressure of pure water is 54.2 mm Hg at room temperature. Molar mass of glucose is 180 g mol^–1 .

The standard electrode potential of M^+/M in aqueous solution does not depend on

20 mL of 0.5 M NaCl is required to coagulate 200 mL of As2S3 solution in 2 hours. The coagulating value of NaCl is____

The vapour pressure vs. temperature curve for a solution solvent system is shown below.

The boiling point of the solvent is _____°C.

Consider the following pairs of solution which will be isotonic at the same temperature. The number of pairs of solutions is/are...... 
A. 1 M aq. NaCl and 2 M aq. Urea 
B. 1 M aq. CaCl₂ and 1.5 M aq. KCl 
C. 1.5 M aq. AlCl₃ and 2 M aq. Na₂SO₄ 
D. 2.5 M aq. KCl and 1 M aq. Al₂(SO₄)₃

80 mole percent of MgCl₂ is dissociated in aqueous solution. The vapour pressure of 1.0 molal aqueous solution of M_gCl₂ at 38°C is ____mm Hg. (Nearest integer)
Given : Vapour pressure of water at 38°C is 50 mm Hg.

20 mL of 0.1 M NaOH is added to 50 mL of 0.1 M acetic acid solution. The pH of the resulting solution is____ x 10^-2 (Nearest integer) 
Given: pKa (CH₃COOH) = 4.76 
log 2 = 0.30 
log 3 = 0.48

A solution of sugar is obtained by mixing 200g of its 25% solution and 500g of its 40% solution (both by mass). The mass percentage of the resulting sugar solution is ______ (Nearest integer)

Formation of which complex, among the following, is not a confirmatory test of Pb²⁺ ions

Which of the following complex has a possibility to exist as meridional isomer?

The set which does not have ambidentate ligands (labeled as (i)) is:

The complex that dissolves in water is:

The ratio of spin-only magnetic moment values \( \mu_{\text{eff}}[Cr(CN)_6]^{3-}/\mu_{\text{eff}}[Cr(H_2O)_6]^{3+} \) is_____