List of top Questions asked in JEE Main

Under steady state condition the potential difference across the capacitor in the circuit is _____ V.

An object AB is placed 15 cm on the left of a convex lens P of focal length 10 cm. Another convex lens Q is now placed 15 cm right of lens P. If the focal length of lens Q is 15 cm, the final image is _____

A copper wire of length 3 m is stretched by 3 mm by applying an external force. The volume of the wire is \( 600 \times 10^{-6} \text{ m}^3 \). The elastic potential energy stored in the wire in stretched condition would be _____J. (Given Young's modulus of copper = \( 1.1 \times 10^{11} \text{ N/m}^2 \))}

Assuming the experimental mass of \( {}^{12}_{6}\text{C} \) as 12 u, the mass defect of \( {}^{12}_{6}\text{C} \) atom is____MeV/\( c^2 \).
(Mass of proton = 1.00727 u, mass of neutron = 1.00866 u, 1 u = 931.5 MeV/\( c^2 \))

A series LCR circuit with \( R = 20\ \Omega, L = 1.6\text{ H and } C = 40\ \mu\text{F} \) is connected to a variable frequency a.c. source. The inductive reactance at resonant frequency is _____ \(\Omega\).

500 mL of 0.2 M \(MnO_4^-\) solution in basic medium when mixed with 500 mL of 1.5 M KI solution, oxidises iodide ions to liberate molecular iodine. This liberated iodine is then titrated with a standard \(M\) thiosulphate solution in presence of starch till the end point. If 300 mL of thiosulphate was consumed, the value of \(x\) is _____.

An alkane (Y) requires 8 moles of oxygen for complete combustion and on chlorination with \(Cl_2/h\nu\), (Y) gives only one monochlorinated product (Z). The total number of primary carbon atoms in (Y) is _____.

Decomposition of a hydrocarbon follows the equation} \[ k = (5.5 \times 10^{11}\, s^{-1})\, e^{\frac{-28000}{T}} \] The activation energy of reaction is _____ kJ mol\(^{-1}\). (Nearest Integer)} Given: \(R = 8.3\, J\,K^{-1}\,mol^{-1}\)}

In a closed flask at 600 K, one mole of \(X_2Y_4(g)\) attains equilibrium as given below :} \[ X_2Y_4(g) \rightleftharpoons 2XY_2(g) \] At equilibrium, 75% \(X_2Y_4(g)\) was dissociated and the total pressure is 1 atm. The magnitude of \(\Delta G^\circ\) (in kJ mol\(^{-1}\)) at this temperature is _____. (Nearest Integer)}

The number of compounds from the following which can undergo reaction with \(Br_2/KOH\) (alcoholic) to give respective products and these products can also be obtained separately by Gabriel phthalimide reaction is :}

Consider the following reaction}

Statement I:} In the above reaction, product formed will be a mixture of benzyl alcohol and iodobenzene.
Statement II:} In the above reaction, the \(-O-CH_2-\) bond is cleaved to give the product. Choose the correct answer.

Consider the following organic reaction sequence. Choose the final product (X) from the following (consider the major product in all intermediate reactions).

An excess of \(AgNO_3\) is added to \(100\) mL of a \(0.05\) M solution of tetraaquodichloridochromium (III) chloride. The number of moles of \(AgCl\) precipitated will be ______\(\times 10^{-3}\). (Nearest integer)}

Treatment of a gas \(X\) with a freshly prepared ferrous sulphate solution gives a compound \(Y\) as a brown ring. The compounds \(X\) and \(Y\) are :

Consider the following reactions. Total number of electrons in the \(\pi\)-bonds and lone pair of electrons in the product (X) is :}

The correct order of first \((\Delta_iH_1)\) and second \((\Delta_iH_2)\) ionisation enthalpy values of Cr and Mn are:}

[A.] \( \Delta_iH_1: Cr>Mn \)
[B.] \( \Delta_iH_2: Cr>Mn \)
[C.] \( \Delta_iH_1: Mn>Cr \)
[D.] \( \Delta_iH_2: Mn>Cr \)

Choose the correct answer.

\(X\) is the product obtained by hydrolysis of prop-1-yne in the presence of mercuric sulphate under dilute acidic medium. \(Y\) is obtained by the reaction of ethanenitrile with methyl magnesium bromide in dry ether followed by hydrolysis. IUPAC name of product obtained from \(X\) and \(Y\) in presence of barium hydroxide followed by heating is :

Given below are two statements:
Statement I:\(F_2O < H_2O < Cl_2O\) is the correct trend in terms of bond angle.
Statement II:\(SiF_4, SnF_4\) and \(PbF_4\) are ionic in nature. Choose the correct answer.

An optically active alkyl bromide \(C_4H_9Br\) reacts with ethanolic KOH to form major compound [A] which reacts with bromine to give compound [B]. Compound [B] reacts with ethanolic KOH and sodamide to give compound [C]. One molecule of water adds to compound [C] on warming with mercuric sulphate and dilute sulphuric acid at \(333\,K\) to form compound [D]. The functional group in compound D is confirmed by :

Given below are two statements:} Statement I:} A mixture of \(C_{12}H_{22}O_{11}\) (sugar) and \(NaCl\) can be separated by dissolving sugar in alcohol, due to differential solubility. Statement II:} Rose essence from rose petals is separated by steam distillation due to its high volatility and insolubility in \(H_2O\). Choose the correct answer.

Which of the following sequences of hybridisation, geometry and magnetic nature are correct for the given coordination compounds?}