List of top Chemistry Questions asked in JEE Main

Consider the following elements In, Tl, Al, Pb, and Ge. The most stable oxidation states of elements with highest and lowest first ionisation enthalpies, respectively, are:

Which of the following statement is true with respect to H$_2$O, NH$_3$ and CH$_4$?
(A) The central atoms of all the molecules are sp$^3$ hybridized.
(B) The H–O–H, H–N–H and H–C–H angles in the above molecules are 104.5°, 107.5° and 109.5° respectively.
(C) The increasing order of dipole moment is CH$_4$<NH$_3$<H$_2$O.
(D) Both H$_2$O and NH$_3$ are Lewis acids and CH$_4$ is a Lewis base.
(E) A solution of NH$_3$ in H$_2$O is basic. In this solution NH$_3$ and H$_2$O act as Lowry-Bronsted acid and base respectively.

A weak acid HA has degree of dissociation x. Which option gives the correct expression of $pH - pK_a$?

The mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dilute HCl is: (Given molar mass of Mg = 24 g/mol)

The elemental composition of a compound is 54.2%C, 9.2%H, and 36.6%O. If the molar mass of the compound is 132 g/mol, the molecular formula of the compound is:

CrCl$_3$.xNH$_3$ can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of 0.558°C. Assuming 100\% ionization of this complex and coordination number of Cr is 6, the complex will be:

Order of limiting molar conductivities of these cations at 298 K is:

2.8 $ \times 10^{-3} $ mol of $ \text{CO}_2 $ is left after removing $ 10^{21} $ molecules from its ‘$ x $’ mg sample. The mass of $ \text{CO}_2 $ taken initially is: Given: $ N_A = 6.02 \times 10^{23} \, \text{mol}^{-1} $

For hydrogen-like species, which of the following graphs provides the most appropriate representation of $ E $ vs $ Z $ plot for a constant $ n $?
[E : Energy of the stationary state, Z : atomic number, n = principal quantum number]

Concentrated nitric acid is labelled as 75%by mass. The volume in mL of the solution which contains 30 g of nitric acid is: Given: Density of nitric acid solution is 1.25 g/mL.

The sum of sigma (σ) and pi (π) bonds in Hex-1,3-dien-5-yne is:

The molar mass of the water insoluble product formed from the fusion of chromite ore $FeCr_2\text{O}_4$ with $Na_2\text{CO}_3$ in presence of $O_2$ is ....... g mol$^{-1}$:

When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is ----- (nearest integer).

The standard reduction potential values of some of the p-block ions are given below. Predict the one with the strongest oxidizing capacity.

Match List - I with List - II.

For the thermal decomposition of $ N_2O_5(g) $ at constant volume, the following table can be formed, for the reaction mentioned below: \[ 2 N_2O_5(g) \rightarrow 2 N_2O_4(g) + O_2(g) \] Given: Rate constant for the reaction is $ 4.606 \times 10^{-2} \text{ s}^{-1} $.

O$_2$ gas will be evolved as a product of electrolysis of:
(A) an aqueous solution of AgNO3 using silver electrodes.
(B) an aqueous solution of AgNO3 using platinum electrodes.
(C) a dilute solution of H2SO4 using platinum electrodes.
(D) a high concentration solution of H2SO4 using platinum electrodes.
Choose the correct answer from the options given below :

What is the shape of the $ \text{ClO}_2^- $ ion according to VSEPR theory?

Resonance in X$_2$Y can be represented as

The enthalpy of formation of X$_2$Y is 80 kJ mol$^{-1}$, and the magnitude of resonance energy of X$_2$Y is:

The element that does not belong to the same period of the remaining elements (modern periodic table) is:

The equilibrium constant for decomposition of $ H_2O $ (g) $ H_2O(g) \rightleftharpoons H_2(g) + \frac{1}{2} O_2(g) \quad (\Delta G^\circ = 92.34 \, \text{kJ mol}^{-1}) $ is $ 8.0 \times 10^{-3} $ at 2300 K and total pressure at equilibrium is 1 bar. Under this condition, the degree of dissociation ($ \alpha $) of water is _____ $\times 10^{-2}$ (nearest integer value). [Assume $ \alpha $ is negligible with respect to 1]

Statement-I: Melting point of neopentane is greater than that of n-pentane.
Statement-II: Neopentane gives only one mono-substituted product.

Identify product [A], [B], and [C] in the following reaction sequence.