List of top Chemistry Questions asked in JEE Main

2-Methyl propyl bromide reacts with C2H5O- and gives 'A' whereas on reaction with C2H5OH it gives 'B'. The mechanism followed in these reactions and the products 'A' and 'B' respectively are
In the following reaction 'X' is
CH3 (CH2)4 CH3 \(\frac{A n h y . A l C l _3 }{HCL\triangle}X\) major product
Which of the following complex is octahedral, diamagnetic and the most stable?

Arrange the following orbitals in decreasing order of energy 
A. $n=3, l =0, m =0$ 
B. $n =4, l =0, m =0$ 
C. $n =3, l =1, m =0$ 
D. $n =3, l =2, m =1$ 
The correct option for the order is :

The mismatched combinations are
A. Chlorophyll - Co 
B. Water hardness - EDTA 
C. Photography - [Ag(CN)2]- 
D. Wilkinson catalyst - [(Ph3P)3 RhCl]  
E. Chelating ligand-D- Penicillamine

Evaluate the following statements for their correctness 
A. The elevation in boiling point temperature of water will be same for $01 \,M \,NaCl$ and $01\, M$ urea 
B. Azeotropic mixtures boil without change in their composition
C. Osmosis always takes place from hypertonic to hypotonic solution 
D. The density of $32 \% H _2 SO _4$ solution having molarity $409\, M$ is approximately $126\, g mL ^{-1}$ 
E. A negatively charged sol is obtained when KI solution is added to silver nitrate solution
Choose the correct answer from the options given below :

When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of $A$?

ClF5 at room temperature is:
Be(OH)2 reacts with Sr(OH)2 to yield an ionic salt. Choose the incorrect option related to this reaction from the following:
What is the purpose of adding gypsum to cement? 

Given below are two statements : 
Statement I : Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green.
Statement II : The green colour observerd is due to the formation of copper(I) metaborate.
In the light of the above statements, choose the most appropriate answer from the options given below :

Which of the following represent the Freundlich adsorption isotherms?




Choose the correct answer from the options given below: 
Which of the following statements are not correct?
A. The electron gain enthalpy of F is more negative than that of Cl.
B. Ionization enthalpy decreases in a group of periodic table.
C. The electronegativity of an atom depends upon the atoms bonded to it.
D. Al2O3 and NO are examples of amphoteric oxides.
Choose the most appropriate answer from the options given below:
The reaction \(\frac{ 1}{2}\)H2(g) + AgCl(s) → H+(aq) + Cl-(aq) + Ag(s) occurs in which of the given galvanic cell.
\(2 I O^ − _3 + x I ^− + 12 H ^+ ⟶ 6 I_ 2 + 6 H _2 O\) What is the value of x?

Which of the following compounds are not used as disinfectants? 
A. Chloroxylenol
B. Bithional
C. Veronal
D. Prontosil
E. Terpineol
Choose the correct answer from the options given below:

The energy of an electron in the first Bohr orbit of hydrogen atom is \(-2.18×10^{-18}J\). Its energy in the third Bohr orbit is ____.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A): The first ionization enthalpy of $3d$ series elements is more than that of group 2 metals
Reason (R): In $3d$ series of elements successive filling of d-orbitals takes place
In the light of the above statements, choose the correct answer from the options given below :

The equilibrium constant for the reaction
\(Zn(s)+Sn^{2+}(aq)⇌Zn^{2+}(aq)+Sn(s)\, is\, 1×10^{20}\) at \(298 K\). 
The magnitude of standard electrode potential of \(Sn/Sn^{2+}\) if \(E^{\degree}_{ Zn^{2+}/Zn}= –0.76V \) is _______ \(×10^{−2} V\). (Nearest integer).
(Given : \(\frac{2.303RT}{ F}\) \(=0.059 V \))

In Dumas method for the estimation of $N _2$, the sample is heated with copper oxide and the gas evolved is passed over :

Assume that the radius of the first Bohr orbit of hydrogen atom is $0.6Å$. The radius of the third Bohr orbit of $He^+$is _______ picometer. (Nearest Integer)
A metal 𝑀 forms hexagonal close-packed structure. The total number of voids in 0.02 mol of it is _______ $×10^{21}$. (Nearest integer).
( Given $N_A=6.02×10^{23}$)
The denticity of the ligand present in the Fehling's reagent is ____ .
Total number of acidic oxides among $N_2O_3,NO_2, N_2O,Cl_2O_7,SO_2,CO,CaO,Na_2O$ and NO is ____ .
At \(298\ K\)
\(N_2( g)+3H_2( g)⇌2NH_3( g),K_1=4×10^5\)
\(N_2( g)+O_2( g)⇌2NO(g),K_2=1.6×10^{12}\)
\(H_2( g)+1 2O_2( g)⇌H_2O(g),K_3=1.0×10^{−13}\)
Based on above equilibria, the equilibrium constant of the reaction, 
\(2NH_3( g)\)+\(\frac5 {2}\) \(O_2( g)⇌2NO(g)+3H_2O(g)\) is _______ \(×10^{−33 }\). (Nearest integer)