List of top Chemistry Questions asked in JEE Main

At $300\, K$, the density of a certain gaseous molecule at $2$ bar is double to that of dinitrogen $(N_2)$ at $4$ bar. The molar mass of gaseous molecule is :

The group having triangular planar structures is :

$\Delta U $ is equal to :

An ideal gas undergoes isothermal expansion at constant pressure. During the process :

Among the following, the incorrect statement is :

For a reaction, $ {A_(g) \to A_(l); \Delta H = - 3RT}$. The correct statement for the reaction is :

1 gram of a carbonate $(M_2CO_3)$ on treatment with excess $HCl$ produces $0.01186$ mole of $CO_2$. The molar mass of $M_2CO_3$ in g $mol^{-1}$ is :

Among the following, correct statement is :

Excess of $NaOH_{(aq)}$ was added to $100\, mL$ of ${ FeCl_3}$ (aq) resulting into $2.14\, g$ of ${Fe(OH)_3}$. The molarity of ${FeCl_3}$ (aq) is : (Given molar mass of ${Fe = 56 \, g \, mol^{-1}}$ and molar mass of ${Cl = 35.5 \, g \, mol^{-1}}$)

What is the standard reduction potential $(E^{\circ}) $ for ${Fe^{3+} \to Fe}$ ? Given that : ${Fe^{2+} + 2e^{-} -> Fe ; E^{\circ}_{Fe^{2+} / Fe} = - 0.47 V }$ ${Fe^{3+} + e^{-} -> Fe^{2+} ; E^{\circ}_{Fe^{3+} / Fe^{2+}} = + 0.77 V }$

Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionisation constant of HA is $10^{-5}$, the ratio of salt to acid concentration in the buffer solution will be :

Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect, is :

What quantity (in mL) of a $45\%$ acid solution of a monoprotic strong acid must be mixed with a $20\%$ solution of the same acid to produce $800\ mL$ of a $29.875\%$ acid solution ?

Which of the following species is not paramagnetic?

On treatment of $100\, mL$ of $0.1\, M$ solution of $CoCl _{3} \cdot 6 H _{2} O$ with excess $AgNO _{3} ; 1.2 \times 10^{22}$ ions are precipitated. The complex is

The number of $S=O$ and $S-OH$ bonds present in peroxodisulphuric acid and pyrosulphuric acid respectively are :

The radius of the second Bohr orbit for hydrogen atom is: (Planck's Const. $h =6 . 6262 \times 10^{-34}\, Js$; mass of electron $=9 . 1091 \times 10^{-31}\, Kg$ charge of electron $e =1 .60210 \times 10^{-19} C$; permittivity of vacuum $\left.\left(\epsilon_{0}\right)=8 \cdot 854185 \times 10^{-12}\, Kg ^{-1}\, m ^{-3} A ^{2}\right)$

The Tyndall effect is observed only when following conditions are satisfied (a) The diameter of the dispersed particles is much smaller than the wavelength of the light used. (b) The diameter of the dispersed particle is not much smaller than the wavelength of the light used (c) The refractive indices of the dispersed phase and dispersion medium are almost similar in magnitude (d) The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude

$pK_a$ of a weak acid (HA) and $pK_b$ of a weak base (BOH) are $3.2$ and $3.4,$ respectively. .The pH of their salt (AB) solution is :

The rate of a reaction quadruples when the temperature changes from $300$ to $310\, K$. The activation energy of this reaction is : (Assume activation energy and pre-exponential factor are independent of temperature; $ln\, 2 = 0.693; R=8.314 \,J$ $mol^{-1} \, K^{-1}$)

Observation of “Rhumann’s purple” is a confirmatory test for the presence of :

Which of the following polymers is synthesized using a free radical polymerization technique ?

Fluorination of an aromatic ring is easily accomplished by treating a diazonium salt with \(\mathrm{HBF_4}\). Which of the following conditions is correct about this reaction ?

The "N" which does not contribute to the basicity for the compound is :

The correct statement about the synthesis of erythritol \(\mathrm{C(CH_2OH)_4}\) used in the preparation of PETN is :