List of top Questions asked in JEE Main

Sea water, which can be considered as a 6 molar (6 M) solution of NaCl, has a density of 2 g mL$^{-1}$. The concentration of dissolved oxygen (O$_2$) in sea water is 5.8 ppm. Then the concentration of dissolved oxygen (O$_2$) in sea water, in x $\times$ 10$^{-4}$ m. x = _______. (Nearest integer)
Given: Molar mass of NaCl is 58.5 g mol$^{-1}$Molar mass of O$_2$ is 32 g mol$^{-1}$.

Half-life of zero-order reaction $ A \to $ product is 1 hour, when initial concentration of reaction is 2.0 mol L$^{-1}$. The time required to decrease concentration of A from 0.50 to 0.25 mol L$^{-1}$ is:

Consider the following molecule (X).

The Structure X is?

Given below are two statements:

Statement (II): Structure III is most stable, as the orbitals having the lone pairs are axial, where the $ \ell p - \beta p $ repulsion is minimum. In light of the above statements, choose the most appropriate answer from the options given below:

The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively:

‘X’ is the number of electrons in $ t_2g $ orbitals of the most stable complex ion among $ [Fe(NH_3)_6]^{3+} $, $ [Fe(Cl)_6]^{3-} $, $ [Fe(C_2O_4)_3]^{3-} $ and $ [Fe(H_2O)_6]^{3+} $. The nature of oxide of vanadium of the type $ V_2O_x $ is:

Consider the following plots of log of rate constant $ k (log k)$ vs $ \frac{1}{T} $ for three different reactions. The correct order of activation energies of these reactions is:

Choose the correct answer from the options given below:

Consider the ground state of an atom (Z = 24). How many electrons are arranged with Azimuthal quantum number $ l = 1 $ and $ l = 2 $ respectively?

Consider the given data: $$ \text{(a) HCl(g) + 10H}_2\text{O(l)} \rightarrow \text{HCl.10} \text{ H}_2\text{O} \quad \Delta H = -69.01 \, \text{kJ/mol}^{-1} $$ $$ \text{(b) HCl(g) + 40H}_2\text{O(l)} \rightarrow \text{HCl.40} \text{ H}_2\text{O} \quad \Delta H = -72.79 \, \text{kJ/mol}^{-1} $$ Choose the correct statement:

The correct order of $ [FeF_6]^{3-} $, $ [CoF_6]^{3-} $,$ [Ni(CO)_4] $ and $ [Ni(CN)_4]^{2-} $ complex species based on the number of unpaired electrons present is:

Match List-I with List-II: List-I

The IUPAC name of the following compound is:

Given below are two statements:
Statement (I): Molal depression constant $ k_f $ is given by $ \frac{M_1 R T_f}{\Delta S_{\text{fus}}} $, where symbols have their usual meaning.
Statement (II): $ k_f $ for benzene is less than the $ k_f $ for water.
In light of the above statements, choose the most appropriate answer from the options given below:

A dipeptide, “x”, on complete hydrolysis gives “y” and “z”; “y” on treatment with aqueous HNO$_2$, produces lactic acid. On the other hand, “z” on heating gives the following cyclic molecule.

Based on the information given, the dipeptide X is: