List of top Questions asked in JEE Main- 2020

A 20.0 mL solution containing 0.2 g impure H₂O₂ reacts completely with 0.316 g of KMnO₄ in acid solution. The purity of H₂O₂ (in %) is ____________ (mol. wt. of H₂O₂ = 34; mol. wt. of KMnO₄ = 158)

Match the following :

(i)	Foam	(a)	smoke
(ii)	Gel	(b)	cell fluid
(iii)	Aerosol	(c)	jellies
(iv)	Emulsion	(d)	rubber
		(e)	froth
		(f)	milk

At 300 K, the vapour pressure of a solution containing 1 mole of n-hexane and 3 moles of n-heptane is 550 mm of Hg. At the same temperature, if one more mole of n-heptane is added to this solution, the vapour pressure of the solution increases by 10 mm of Hg. What is the vapour pressure in mm Hg of n-heptane in its pure state ______ ?

The mass of ammonia in grams produced when 2.8 kg of dinitrogen quantitatively reacts with 1 kg of dihydrogen is ________.

If 75% of a first order reaction was completed in 90 minutes, 60% of the same reaction would be completed in approximately (in minutes) __________.
(Take : \(\log 2 = 0.30\); \(\log 2.5 = 0.40\))

Among statements (a) - (d), the correct ones are :
(a) Lime stone is decomposed to CaO during the extraction of iron from its oxides.
(b) In the extraction of silver, silver is extracted as an anionic complex.
(c) Nickel is purified by Mond's process.
(d) Zr and Ti are purified by Van Arkel method.

The ionic radii of \(\mathrm{O^{2-}}\), \(\mathrm{F^-}\), \(\mathrm{Na^+}\) and \(\mathrm{Mg^{2+}}\) are in the order :

On heating, lead (II) nitrate gives a brown gas (A). The gas (A) on cooling changes to a colourless solid/liquid (B). (B) on heating with NO changes to a blue solid (C). The oxidation number of nitrogen in solid (C) is :

Which of the following will react with \(\mathrm{CHCl_3}\) + alc. KOH ?

For one mole of an ideal gas, which of these statements must be true ?
(a) U and H each depends only on temperature
(b) Compressibility factor z is not equal to 1
(c) \(C_{P,m} - C_{V,m} = R\)
(d) \(dU = C_V dT\) for any process

The region in the electromagnetic spectrum where the Balmer series lines appear is :

The pair in which both the species have the same magnetic moment (spin only) is :

The elements with atomic numbers 101 and 104 belong to, respectively :

What are the functional groups present in the structure of maltose?

The number of isomers possible for \(\mathrm{[Pt(en)(NO_2)_2]}\) is :

In the line spectra of hydrogen atom, difference between the largest and the shortest wavelengths of the Lyman series is 304 \(\mathrm{\AA}\). The corresponding difference for the Paschen series (in \(\mathrm{\AA}\)) is ____.

A closed vessel contains 0.1 mole of a monoatomic ideal gas at 200 K. If 0.05 mole of the same gas at 400 K is added to it, the final equilibrium temperature (in K) of the gas in the vessel will be close to _______.

A circular disc of mass M and radius R is rotating about its axis with angular speed \(\omega_1\). If another stationary disc having radius \(\frac{R}{2}\) and same mass M is dropped co-axially on to the rotating disc. Gradually both discs attain constant angular speed \(\omega_2\). The energy lost in the process is p% of the initial energy. Value of p is __________.

Choose the correct option relating wavelengths of different parts of electromagnetic wave spectrum :

Particle A of mass \(m_A = \frac{m}{2}\) moving along the x-axis with velocity \(v_0\) collides elastically with another particle B at rest having mass \(m_B = \frac{m}{3}\). If both particles move along the x-axis after the collision, the change \(\Delta\lambda\) in de-Broglie wavelength of particle A, in terms of its de-Broglie wavelength (\(\lambda_0\)) before collision is :

The specific heat of water \(= 4200\ \mathrm{J\,kg^{-1}K^{-1}}\) and the latent heat of ice \(= 3.4 \times 10^{5}\ \mathrm{J\,kg^{-1}}\). 100 grams of ice at \(0^{\circ}\mathrm{C}\) is placed in 200 g of water at \(25^{\circ}\mathrm{C}\). The amount of ice that will melt as the temperature of water reaches \(0^{\circ}\mathrm{C}\) is close to (in grams) :

A beam of plane polarised light of large cross-sectional area and uniform intensity of \(3.3\ \mathrm{W\,m^{-2}}\) falls normally on a polariser (cross sectional area \(3 \times 10^{-4}\ \mathrm{m^2}\)) which rotates about its axis with an angular speed of \(31.4\ \mathrm{rad/s}\). The energy of light passing through the polariser per revolution, is close to :

For a transverse wave travelling along a straight line, the distance between two peaks (crests) is 5 m, while the distance between one crest and one trough is 1.5 m. The possible wavelengths (in m) of the waves are :

Match the \(C_P/C_V\) ratio for ideal gases with different type of molecules :

Molecule Type	\(C_P/C_V\)
(A) Monatomic	(I) 7/5
(B) Diatomic rigid molecules	(II) 9/7
(C) Diatomic non-rigid molecules	(III) 4/3
(D) Triatomic rigid molecules	(IV) 5/3

If the equation of a plane P, passing through the intersection of the planes, \(x+4y-z+7=0\) and \(3x+y+5z=8\) is \(ax+by+6z=15\) for some \(a,b\in\mathbf{R}\), then the distance of the point (3, 2, \(-1\)) from the plane P is ______.