List of top Questions asked in JEE Main- 2019

Match the refining methods (Column I) with metals (Column II).

Column I (Refining Methods)	Column II (Metals)
(I) Liquation	(a) Zr
(II) Zone Refining	(b) Ni
(III) Mond Process	(c) Sn
(IV) Van Arkel Method	(d) Ga

The alloy used in the construction of aircrafts is :

Consider the statements S1 and S2
S1 : Conductivity always increases with decrease in the concentration of electrolyte.
S2 : Molar conductivity always increases with decrease in the concentration of electrolyte.
The correct option among the following is :

A gas undergoes physical adsorption on a surface and follows the given Freundlich adsorption isotherm equation
\(\frac{x}{m} = kp^{0.5}\)
Adsorption of the gas increase with :

Increasing rate of \(\mathrm{S_N1}\) reaction in the following compounds is :

Consider the hydrated ions of \(\mathrm{Ti^{2+}}\), \(\mathrm{V^{2+}}\), \(\mathrm{Ti^{3+}}\), and \(\mathrm{Sc^{3+}}\). The correct order of their spin-only magnetic moments is :

Major products of the following reaction are :

A bacterial infection in an internal wound grows as \(N'(t) = N_0\exp(t)\), where the time \(t\) is in hours. A dose of antibiotic, taken orally, needs 1 hour to reach the wound. Once it reaches there, the bacterial population goes down as \(\frac{dN}{dt} = -5N^2\). What will be the plot of \(\frac{N_0}{N}\) vs. \(t\) after 1 hour?

During the change of \(\mathrm{O_2}\) to \(\mathrm{O_2^-}\), the incoming electron goes to the orbital :

At 300 K and 1 atmospheric pressure, 10 mL of a hydrocarbon required 55 mL of \(\mathrm{O_2}\) for complete combustion, and 40 mL of \(\mathrm{CO_2}\) is formed. The formula of the hydrocarbon is :

Consider the following statements
(a) The pH of a mixture containing 400 mL of 0.1 M \(\mathrm{H_2SO_4}\) and 400 mL of 0.1 M NaOH will be approximately 1.3
(b) Ionic product of water is temperature dependent.
(c) A monobasic acid with Ka = \(10^{-5}\) has pH = 5. The degree of dissociation of this acid is 50 %.
(d) The Le Chatelier's principle is not applicable to common-ion effect.
The correct statements are :

Three complexes,
\([\mathrm{CoCl(NH_3)_5}]^{2+}\) (I),
\([\mathrm{Co(NH_3)_5H_2O}]^{3+}\) (II) and
\([\mathrm{Co(NH_3)_6}]^{3+}\) (III)
absorb light in the visible region. The correct order of the wavelength of light absorbed by them is :

The species that can have a trans-isomer is :
(en = ehane-1, 2-diamine, ox = oxalate)

A process will be spontaneous at all temperatures if :

The major product of the following reaction is :

The major product of the following reaction is :

The major product of the following reaction is :

The increasing order of the reactivity of the following compounds towards electrophilic aromatic substitution reactions is :

At room temperature, a dilute solution of urea is prepared by dissolving 0.60 of urea in 360 g of water. If the vapour pressure of pure water at this temperature is 35 mm Hg, lowering of vapour pressure will be. (molar mass of urea = 60 g mol\(^{-1}\))

A stationary source emits sound waves of frequency 500 Hz. Two observers moving along a line passing through the source detect sound to be of frequencies 480 Hz and 530 Hz. Their respective speeds are, in ms^-1, (Given speed of sound = 300 m/s)

The graph between \(|\psi|^2\) and r (radial distance) is shown below. This represents :

n moles of an ideal gas with constant volume heat capcity \(C_V\) undergo an isobaric expansion by certain volume. The ratio of the work done in the process, to the heat supplied is :

The displacement of a damped harmonic oscillator is given by
\(x(t)=e^{-0.1t}\cos(10\pi t+\phi)\).
Here t is in seconds. The time taken for its amplitude of vibration to drop to half of its initial value is close to :

A ray of light AO in vacuum is incident on a glass slab at angle \(60^\circ\) and refracted at angle \(30^\circ\) along OB as shown in the figure. The optical path length of light ray from A to B is:

A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2 kW. If the current in the secondary coil is 10A, then the input voltage and current in the primary coil are :