List of top Chemistry Questions asked in JEE Main

If $\lambda_{0}$ and $\lambda$ be the threshold wavelength and wavelength of incident light, the velocity of photoelectron ejected from the metal surface is :

The energy of an electron in first Bohr orbit of $H$ - atom is $- 13.6\, eV$. The energy value of electron in the excited state of $Li^{2+}$ is :

Based on the equation : $\Delta E = -2.0 \times 10^{-18} J \left(\frac{1}{n^{2}_{2}}-\frac{1}{n^{2}_{1}}\right)$ the wavelength of the light that must be absorbed to excite hydrogen electron from level n=l to level n=2 will be : $\left(h = 6.625 \times 10^{-34} \,Js, C= 3\times10^{8} \,ms^{-1}\right)$

If $m$ and $e$ are the mass and charge of the revolving electron in the orbit of radius $r$ for hydrogen atom, the total energy of the revolving electron will be :

Excited hydrogen atom emits light in the ultraviolet region at $2.47 \times 10^{15}\, Hz$. With this frequency, the energy of a single photon is : $(h = 6.63 \times 10^{-34}\, Js)$

In which of the following reactions $ H_2O_2 $ acts as a reducing agent? (a) $H_2O_2 + 2H^+ + 2e^- \rightarrow 2H_2O $ (d) $ H_2O_2 - 2e^- \rightarrow O_2 + 2H^+ $ (c) $H_2O_2 + 2e^- \rightarrow 2OH^- $ (d) $H_2O_2 + 2OH^- - 2e^- \rightarrow O_2 + 2H_2O $

Copper becomes green when exposed to moist air for a long period. This is due to:

If Z is a compressibility factor, van der Waals equation at low pressure can be written as

Van der Waal's equation for a gas is stated as, $p = \frac{nRT}{V-nb}-a\left(\frac{n}{V}\right)^{2}.$ This equation reduces to the perfect gas equation, $p = \frac{nRT}{V}$ when ,

The initial volume of a gas cylinder is 750.0 \,mL. If the pressure of gas inside the cylinder changes from $840.0 \,mm$ Hg to 360.0 mm Hg, the final volume the gas will be :

Given below are the half-cell reactions $Mn ^{2+}+2 e ^{-} \rightarrow Mn ; E ^{\circ}=-1.18 \,V$ $\left( Mn ^{3+}+ e ^{-} \rightarrow Mn ^{2+}\right) ; E ^{\circ}=+1.51 \,V$ The $ E ^{\circ} $ for $3 \,Mn ^{2+} \rightarrow Mn +2 Mn ^{3+}$ will be

The equivalent conductance of $NaCl$ at concentration $C$ and at infinite dilution are $\lambda_C$ and $\lambda_\infty$ respectively. The correct relationship between $\lambda_C$ and $\lambda_\infty$ is given as (where, the constant $B$ is positive)

Resistance of $0.2\, M$ solution of an electrolyte is $50 \,\Omega$. The specific conductance of the solution of $0.5 \,M$ solution of same electrolyte is $1.4\, S \, m^{-1}$ and resistance of same solution of the same electrolyte is $280 \,\Omega$ . The molar conductivity of $0.5\, M$ solution of the electrolyte in $S\,m^2 \,mol^{-1}$ is

Which of the following arrangements represents the increasing order (smallest to largest) of ionic radii of the given species $O^{2-}, S^{2-}, N^{3-}, P^{3-} ?$

The correct statement for the molecule, $CsI_3$ is

Hydrogen peroxide acts both as an oxidising and as a reducing agent depending upon the nature of the reacting species. In which of the following cases $H_2O_2$ acts as a reducing agent in acid medium ?

How many electrons would be required to deposit $6.35 \,g$ of copper at the cathode during the electrolysis of an aqueous solution of copper sulphate ? (Atomic mass of copper $= 63.5\, u, N_A =$ Avogadro's constant) :

The total number of octahedral void(s) per atom present in a cubic close packec structure is :-

Dissolving $120 \,g$ of a compound of (mol. wt. $60$) in $1000 \,g$ of water gave a solution of density $1.12 \,g/mL$. The molarity of the solution is :

Similarity in chemical properties of the atoms of elements in a group of the Periodic table is most closely related to :

Which series of reactions correctly represents chemical relations related to iron and its compound?

Among the following oxoacids, the correct decreasing order of acidic strength is

Which of the following statements about $Na_2O_2$ is not correct?

For the reaction, 3A + 2B $\to$ C + D, the differential rate law can be written as :

The correct order of bond dissociation energy among $N_2, O_2, O_2^-$ is shown in which of the following arrangements ?