List of top Chemistry Questions asked in JEE Main

The principle of column chromatography is :
The metal that forms nitride by reacting directly with $N_2$ of air, is :
The coordination numbers of Co and Al in ${ [Co(Cl)(en)2]Cl}$ and ${K3[Al(C2O4)3]}$, respectively, are : (en=ethane-1,2-diamine)
The pH of a 0.02M $NH_4Cl$ solution will be [given $K_b(NH_4OH) = 10^{-5}$ and log2=0.301]
A solution of sodium sulfate contains $92\, g$ of ${Na^{+}}$ ions per kilogram of water. The molality of ${Na^{+}}$ ions in that solution in ${mol \; kg^{-1}}$ is:
The number of bridging $CO$ ligand (s) and $Co - Co$ bond (s) in $ {CO_2(CO)_8}$, respectively are :
The idea of froth floatation method came from a person $X$ and this method is related to the process $Y$ of ores. $X$ and $Y$, respectively, are:
Consider the given plots for a reaction obeying Arrhenius equation $(0^{\circ}C < T < 300^{\circ}C)$ : ($k$ and $E_a$ are rate constant and activation energy, respectively) Choose the correct option :
The metal used for making $X$-ray tube window is :
Which of the following is a condensation polymer?
Which is wrong with respect to our responsibility as a human being to protect our environment ?
Poly-$\beta$-hydroxybutyrate-co-$\beta$ hydroxyvalerate (PHBV) is a copolymer of___.
The correct statement regarding the given Ellingham diagram is:
When the first electron gain enthalpy $( \Delta_{eg}H) $ of oxygen is $-141\, kJ/mol$, its second electron gain enthalpy is :
The number of 2 -centre- 2 -electron and 3-centre-2-electron bonds in $B _{2} H _{6}$, respectively, are :
The correct decreasing order for acid strength is :
Element 'B' forms ccp structure and 'A' occupies half of the octahedral voids, while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is :
The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol $kg^{-1}$) of the aqueous solution is
The upper stratosphere consisting of the ozone layer protects us from the sun's radiation that falls in the wavelength region of :

In order to oxidise a mixture one mole of each of \(${FeC2O_4, Fe2(C2O4)3, FeSO4}$\) and \(${Fe2(SO4)3}$\) in acidic medium, the number of moles of \(${KMnO_4 }$\) required is -

A compound of formula $A_2B_3$ has the hcp lattice. Which atom forms the hcp lattice and what fraction of tetrahedral voids is occupied by the other atoms :
At $100^{\circ} \,C$, copper $(Cu)$ has $FCC$ unit cell structure with cell edge length of $x\, ?$ What is the approximate density of $Cu$ (in $g\, cm^{-3})$ at this temperature ? [Atomic Mass of $Cu = 63.55\,u]$
The correct order of hydration enthalpies of alkali metal ions is -
A water sample has ppm level concentration of the following metals: $Fe = 0.2; Mn = 5.0; Cu = 3.0; Zn = 5.0.$ The metal that makes the water sample unsuitable drinking is
The correct sequence of thermal stability of the following carbonates is