List of top Questions asked in JEE Main

Given below are two statements:

Statement (I): The first ionization energy of Pb is greater than that of Sn.
Statement (II): The first ionization energy of Ge is greater than that of Si.

In light of the above statements, choose the correct answer from the options given below:

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

$\mathrm{KMnO}_{4}$ acts as an oxidising agent in acidic medium. ' X ' is the difference between the oxidation states of Mn in reactant and product. ' Y ' is the number of ' d ' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of $\mathrm{X}+\mathrm{Y}$ is _______ .

The species which does not undergo disproportionation reaction is:

For a reaction, $$ {N}_2{O}_5(g) \rightarrow 2{NO}_2(g) + \frac{1}{2} {O}_2(g) $$ in a constant volume container, no products were present initially. The final pressure of the system when 50% of the reaction gets completed is:

In Carius method for estimation of halogens, 180 mg of an organic compound produced 143.5 mg of AgCl. The percentage composition of chlorine in the compound is ___________%. [Given: Molar mass in g mol$^{-1}$ of Ag = 108, Cl = 35.5]

Given below are two statements: Statement (I): The boiling points of alcohols and phenols increase with increase in the number of C-atoms.
Statement (II): The boiling points of alcohols and phenols are higher in comparison to other classes of compounds such as ethers and haloalkanes. In the light of the above statements, choose the correct answer from the options given below:

Given below are two statements.

In the light of the above statements, choose the correct answer from the options given below:

Density of 3 M NaCl solution is 1.25 g/mL. The molality of the solution is:

Identify the inorganic sulphides that are yellow in colour:
(A) $ ({NH}_4)_2{S} $
(B) $ {PbS} $
(C) $ {CuS} $
(D) $ {As}_2{S}_3 $
(E) $ {As}_2{S}_5 $
Choose the correct answer from the options given below:

Consider an elementary reaction: \[ A(g) + B(g) \rightarrow C(g) + D(g) \] If the volume of the reaction mixture is suddenly reduced to $ \frac{1}{3} $ of its initial volume, the reaction rate will become $ x $ times of the original reaction rate. The value of $ x $ is:

The purification method based on the following physical transformation is: \[ {Solid} \xrightarrow{{Heat}} {Vapour} \xrightarrow{{Cool}} {Solid} \]

The major product of the following reaction is:

The total number of compounds from below when treated with hot KMnO4 giving benzoic acid is:

Identify correct statements: (A) Primary amines do not give diazonium salts when treated with ${NaNO}_2$ in acidic condition.
(B) Aliphatic and aromatic primary amines on heating with ${CHCl}_3$ and ethanolic ${KOH}$ form carbylamines.
(C) Secondary and tertiary amines also give carbylamine test.
(D) Benzenesulfonyl chloride is known as Hinsberg’s reagent.
(E) Tertiary amines react with benzenesulfonyl chloride very easily.
Choose the correct answer from the options given below:

The correct order of basic strength of the following molecules is:
(A) $\text{C}_6\text{H}_4\text{NH}_2\text{O}$
(B) $\text{C}_6\text{H}_4\text{NH}_2\text{MeO}$
(C) $\text{C}_6\text{H}_4\text{NH}_2\text{NO}_2$
(D) $\text{C}_6\text{H}_4\text{NH}_2\text{CH}_3$

The correct order of basicity for the following molecules is:

The descending order of basicity of following amines is :

Choose the correct answer from the options given below :

In the reaction $ 2A + B \rightarrow C $, if the rate law is $ \text{Rate} = k[A]^2[B] $, what is the overall order of the reaction?

Consider an elementary reaction: \[ A(g) + B(g) \rightarrow C(g) + D(g) \] If the volume of the reaction mixture is suddenly reduced to $ \frac{1}{3} $ of its initial volume, the reaction rate will become $ x $ times of the original reaction rate. The value of $ x $ is:

The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K. If the energy barrier with respect to reactant energy for such isomeric transformation is 191.48 kJ mol$^{-1}$ and the frequency factor is $10^{20}$, the time required for 50% molecules of A to become B is ________________________ picoseconds (nearest integer). [R = 8.314 J K$^{-1}$ mol$^{-1}$]

In a first order decomposition reaction, the time taken for the decomposition of reactant to one fourth and one eighth of its initial concentration are $ t_1 $ and $ t_2 $ (s), respectively. The ratio $ t_1 / t_2 $ will be:

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:

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:

Reaction A(g) → 2B(g) + C(g) is a first-order reaction. It was started with pure A.
The following table shows the pressure of the system at different times:

Which of the following options is incorrect?