List of top Chemistry Questions asked in JEE Main

Which of the following oxoacids of sulphur contains \(S\) in two different oxidation states?

In neutral or faintly alkaline medium, KMnO₄ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be

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

Statement-I: An alloy of lithium and magnesium is used to make aircraft plates. 

Statement-II: The magnesium ions are important for cell-membrane integrity. 

In the light of the above statements, choose the correct answer from the options given below:

0.2 g of an organic compound was subjected to estimation of nitrogen by Duma’s method in which volume of N2 evolved (at STP) was found to be 22.400 mL. The percentage of nitrogen in the compound is _____. [nearest integer] 
(Given : Molar mass of N₂ is 28 g mol^–1, Molar volume of N₂ at STP : 22.4L)

In alanylglycylleucylalanyvaline, the number of peptide linkages is__,

At 300 K, a sample of 3.0 g of gas A occupies the same volume as 0.2 g of hydrogen at 200 K at the same pressure. The molar mass of gas A is _____ g mol^–1. (nearest integer)
Assume that the behaviour of gases as ideal.
(Given: The molar mass of hydrogen (H₂) gas is 2.0 g mol^–1).

A company dissolves \(‘X’\) amount of \(CO_2\) at \(298\ K\) in \(1\) litre of water to prepare soda water. \(X\) = _____ \(× 10^{–3}\) g. (nearest integer)
(Given: partial pressure of \(CO_2\) at \(298\ K = 0.835\) bar. Henry’s law constant for \(CO_2\) at \(298\ K = 1.67\) Kbar. Atomic mass of \(H\), \(C\) and \(O\) is \(1\), \(12\), and \(6\) g mol^–1, respectively)

\(PCl_5\) dissociates as
\(PCl_5(g) ⇌ PCl_3(g)+ Cl_2(g)\)
\(5\) moles of \(PCl_5\) are placed in a \(200\) litre vessel which contains \(2\) moles of \(N_2\) and is maintained at \(600\ K\). The equilibrium pressure is \(2.46\) atm. The equilibrium constant Kp for the dissociation of \(PCl_5\) is ______ \(× 10^{–3}\). (nearest integer) 
(Given: \(R = 0.082\) L atm K^–1 mol^–1; Assume ideal gas behaviour)

The resistance of a conductivity cell containing \(0.01\) M KCl solution at \(298\ K\) is \(1750\ Ω\). If the conductivity of \(0.01\) M KCl solution at \(298\ K\) is \(0.152×10^{–3}\) S cm^–1, then the cell constant of the conductivity cell is ______ \(×10^{–3}\) cm^–1.

(a) Baryte,
(b) Galena, 
(c) Zinc blende and 
(d) Copper pyrites. 
How many of these minerals are sulphide based?

Manganese (VI) has ability to disproportionate in acidic solution. The difference in oxidation states of two ions it forms in acidic solution is _____.

A 2.0 g sample containing MnO₂ is treated with HCl liberating Cl₂. The Cl₂ gas is passed into a solution of KI and 60.0 mL of 0.1 M Na₂S₂O₃ is required to titrate the liberated iodine. The percentage of MnO₂ in the sample is ______. (Nearest integer)
[Atomic masses (in u) Mn = 55; Cl = 35.5; O = 16, I = 127, Na = 23, K = 39, S = 32]

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

4.0 L of an ideal gas is allowed to expand isothermally into vacuum until the total volume is 20 L. The amount of heat absorbed in this expansion is ____ L atm.

The vapour pressures of two volatile liquids A and B at 25°C are 50 Torr and 100 Torr, respectively. If the liquid mixture, contains 0.3 mole fraction of A, then the mole fraction of liquid B in the vapour phase is \(\frac {x}{17}\). The value of x is _____.

The solubility product of a sparingly soluble salt \(A_2X_3\) is \(1.1 × 10^{–23}\). If the specific conductance of the solution is \(3×10^{–5}\) S m^–1, the limiting molar conductivity of the solution is \(x×10^{–3}\) S m² mol^–1. The value of x is _______.

The quantity of electricity of Faraday needed to reduce \(1\) mol of \(Cr_2O_7^{2-}\) to \(Cr^{3+}\) is

For a first order reaction \(A → B\), the rate constant, \(k = 5.5×10^{–14}s^{–1}\). The time required for 67% completion of reaction is \(x×10^{–1}\) times the half life of reaction. The value of \(x\) is _____. (Nearest integer)

Number of complexes which will exhibit synergic bonding amongst, \([Cr(CO)_6]\), \([Mn(CO)_5]\) and \([Mn_2(CO)_{10}]\) is ________.

lf the work function of a metal is 6.63 × 10^–19 J, the maximum wavelength of the photon required to remove a photoelectron from the metal is ______ nm. (Nearest integer)
[Given : h = 6.63 × 10^–34 J s, and c = 3 × 10⁸ m s^–1]

Which amongst the following is not a pesticide?