List of top Chemistry Questions asked in JEE Main

Which of the following compounds will be suitable for Kjeldahl's method for nitrogen estimation?

Two compounds I and II are eluted by column chromatography (adsorption of I > II). Which one of following is a correct statement ?

At 320 K, a gas A2 is 20% dissociated to A(g). The standard free energy change at 320 K and 1 atm in J mol$^{-1}$ is approximately : (R=8.314 JK$^{-1}$ mol$^{-1}$; ln 2=0.693; ln 3=1.098)

An aqueous solution contains an unknown concentration of $Ba^{2+}$. When $50 \,mL$ of a $1\, M$ solution of $Na_2SO_4$ is added, $BaSO_4$ just begins to precipitate. The final volume is $500 \,mL$. The solubility product of $BaSO_4$ is $1 \times 10^{-10}$. What is the original concentration of $Ba^{2+}$ ?

Which of the following salts is the most basic in aqueous solution?

A sample of $NaClO_3$ is converted by heat to NaCl with a loss of $0.16\, g$ of oxygen. The residue is dissolved in water and precipitated as $AgCl$. The mass of $AgCl$ (in g) obtained will be : (Given : Molar mass of $AgCl = 143.5\, g\, mol^{-1}$)

For which of the following reactions, $\Delta H$ is equal to $\Delta U$ ?

For which of the following processes, $\Delta S$ is negative ?

Which of following lines correctly show the temperature dependence of equilibrium constant $K$, for an exothermic reaction ?

$\Delta_{r} G^{\circ}$ at $500 \,K$ for substance 'S' in liquid state and gascous state are $+100.7 \,kcal\, mol ^{-1} $ and $+103 \,kcal \,mol ^{-1}$, respectively. Vapour pressure of liquid ' S ' at $500\, K$ is approximately equal to $\left(R=2 \,cal K ^{-1} \,mol ^{-1}\right)$

Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying $0.5\, V$ when the radiation of $250\, nm$ is used. The work function of the metal is :

Which of the following statements is false?

For standardizing NaOH solution, which of the following is used as a primary standard ?

When an electric current is passed through acidified water, $112\, mL$ of hydrogen gas at N.T.P. was collected at the cathode in $965$ seconds. The current passed, in ampere, is :

In $KO_2$, the nature of oxygen species and the oxidation state of oxygen atom are, respectively :

In the molecular orbital diagram for the molecular ion, $N_2{^{+}}$, the number of electrons in the $\sigma_{2p}$ molecular orbital is :

At $518^{\circ} C$ , the rate of decomposition of sample of gaseous acetaldehyde, initially at a pressure of $363$ Torr, was $1. 00$ Torr $s^{-1}$ when $5\%$ had reacted and $0.5$ Torr $s^{-1}$ when $33\%$ had reacted. The order of the reaction is -

Hydrogen peroxide oxidises $[Fe(CN)6]^{4-}$ to $[Fe(CN)6]^{3-}$ in acidic medium but reduces $[Fe(CN)6]^{3-}$ to$[Fe(CN)6]^{4-}$ in alkaline medium. The other products formed are, respectively

The oxidation states of $Cr$ in $ [Cr(H_2O)_6]Cl_3, [Cr(C_6H_6)_2]$, and $K_2[Cr(CN)_2(O)_2(O_2)(NH_3)]$ respectively are :

How long (approximate) should water be electrolysed by passing through $100$ amperes current so that the oxygen released can completely burn $27.66 \,g$ of diborane ? (Atomic weight of $B = 10.8\, u$ )

When $9.65\,A$ current was passed for $1.0\, hour$ into nitrobenzene in acidic medium, the amount of p-aminophenol produced is_____.

In Wilkinson?s catalyst, the hybridization of central metal ion and its shape are respectively :

The number of $P - O$ bonds in $P_4O_6$ is :

Two moles of an ideal monoatomic gas occupies a volume $V$ at $27^{\circ}C$. The gas expands adiabatically to a volume $2V$. Calculate $(a)$ the final temperature of the gas and $(b) $ change in its internal energy -

Which of the following statements is false?