List of top Questions asked in JEE Main

An organic compound [A], molecular formula \(\mathrm{C_{10}H_{20}O_2}\) was hydrolyzed with dilute sulphuric acid to give a carboxylic acid [B] and an alcohol [C]. Oxidation of [C] with \(\mathrm{CrO_3 - H_2SO_4}\) produced [B]. Which of the following strucutres are not possible for [A]?

Which one of the following compounds possesses the most acidic hydrogen?

The Kjeldahl method of Nitrogen estimation fails for which of the following reaction products?
(a) nitrobenzene with Sn/HCl
(b) benzonitrile (C₆H₅CN) with LiAlH₄
(c) benzyl cyanide (C₆H₅CH₂CN) with (i) SnCl₂ + HCl, (ii) H₂O
(d) aniline with NaNO₂/HCl

Which of the following compounds produces an optically inactive compound on hydrogenation?

The total number of monohalogenated organic products in the following (including stereoisomers) reaction is ______.

A wire carrying current \(I\) is bent in the shape ABCDEFA as shown, where rectangle ABCDA and ADEFA are perpendicular to each other. If the sides of the rectangles are of lengths \(a\) and \(b\), then the magnitude and direction of magnetic moment of the loop ABCDEFA is

The figure shows a region of length '\(l\)' with a uniform magnetic field of 0.3 T in it and a proton entering the region with velocity \(4\times10^{5}\ \mathrm{ms^{-1}}\) making an angle \(60^\circ\) with the field. If the proton completes 10 revolution by the time it cross the region shown, '\(l\)' is close to
(mass of proton = \(1.67\times10^{-27}\) kg, charge of the proton = \(1.6\times10^{-19}\) C)

The displacement time graph of a particle executing S.H.M is given in figure :
(sketch is schematic and not to scale)

Which of the following statements is/are true for this motion?
(A) The force is zero at \(t = \frac{3T}{4}\)
(B) The acceleration is maximum at \(t = T\)
(C) The speed is maximum at \(t = \frac{T}{4}\)
(D) The P.E. is equal to K.E. of the oscillation at \(t = \frac{T}{2}\)

In the following digital circuit, what will be the output at 'Z', when the input (A, B) are (1, 0), (0, 0), (1, 1), (0, 1)

A potentiometer wire PQ of 1 m length is connected to a standard cell E₁. Another cell E₂ of emf 1.02 V is connected with a resistance 'r' and switch S (as shown in figure). With switch S open, the null position is obtained at a distance of 49 cm from Q. The potential gradient in the potentiometer wire is :

A square shaped hole of side \(l = \frac{a}{2}\) is carved out at a distance \(d = \frac{a}{2}\) from the centre 'O' of a uniform circular disk of radius \(a\). If the distance of the centre of mass of the remaining portion from O is \(-\frac{a}{X}\), value of \(X\) (to the nearest integer) is :

An ideal cell of emf 10 V is connected in circuit shown in figure. Each resistance is \(2\ \Omega\). The potential difference (in V) across the capacitor when it is fully charged is ______.

Two compounds A and B with same molecular formula (\(\mathrm{C_3H_6O}\)) undergo Grignard's reaction with methylmagnesium bromide to give products C and D. Products C and D show following chemical tests.

Test	C	D
Ceric ammonium nitrate Test	Positive	Positive
Lucas Test	Turbidity obtained after five minutes	Turbidity obtained immediately
Iodoform Test	Positive	Negative

C and D respectively are :

Simplified absorption spectra of three complexes ((i), (ii) and (iii)) of \(\mathrm{Mn^{+}}\) ion are provided below; their \(\lambda_{max}\) values are marked as A, B and C respectively. The correct match between the complexes and their \(\lambda_{max}\) values is

(i) \(\mathrm{[M(NCS)_6]^{(-6+n)}}\)
(ii) \(\mathrm{[MF_6]^{(-6+n)}}\)
(iii) \(\mathrm{[M(NH_3)_6]^{n+}}\)

The correct observation in the following reactions is :

(Sucrose \(\xrightarrow[\text{(Hydrolysis)}]{\text{Glycosidic bond cleavage}}\) A + B \(\xrightarrow{\text{Seliwanoff's reagent}}\) ?)

The major product of the following reaction is :

An organic compound ‘A’ (\(\mathrm{C_9H_{10}O}\)) when treated with conc. HI undergoes cleavage to yield compounds ‘B’ and ‘C’. ‘B’ gives yellow precipitate with \(\mathrm{AgNO_3}\) where as ‘C’ tautomerizes to ‘D’. ‘D’ gives positive iodoform test. ‘A’ could be

Arrange the following labelled hydrogens in decreasing order of acidity :

Consider the reaction sequence given below:

Which of the following statements is true?

A cylindrical vessel containing a liquid is rotated about its axis so that the liquid rises at its sides as shown in the figure. The radius of vessel is 5 cm and the angular speed of rotation is \(\omega\) rad s\(^{-1}\). The difference in the height, \(h\) (in cm) of liquid at the centre of vessel and at the side will be :

Shown in the figure is rigid and uniform one meter long rod \(AB\) held in horizontal position by two strings tied to its ends and attached to the ceiling. The rod is of mass \(m\) and has another weight of mass \(2m\) hung at a distance of 75 cm from \(A\). The tension in the string at \(A\) is :

A uniform cylinder of mass \(M\) and radius \(R\) is to be pulled over a step of height \(a\) (\(a \lt R\)) by applying a force \(F\) at its centre \(O\) perpendicular to the plane through the axes of the cylinder on the edge of the step (see figure). The minimum value of \(F\) required is :

A spherical mirror is obtained as shown in the figure from a hollow glass sphere. If an object is positioned in front of the mirror, what will be the nature and magnification of the image of the object?
(Figure drawn as schematic and not to scale)

A charged particle (mass \(m\) and charge \(q\)) moves along X-axis with velocity \(V_0\). When it passes through the origin it enters a region having uniform electric field \(\vec{E}=-E\hat{j}\) which extends upto \(x=d\). Equation of path of electron in the region \(x \gt d\) is

The major product obtained from \(\mathrm{E_2}\) - elimination of 3-bromo-2-fluoropentane is