List of top Chemistry Questions asked in JEE Main

Adsorption' principle is used for which of the following purification method?
The correct sequence of electron gain enthalpy of the elements listed below is
A. Ar 
B. Br 
C. F 
D. S 
Choose the most appropriate from the options given below:
Given below are two statements:
One is labelled as Assertion A and the other is labelled as Reason R: 
Assertion A: Alcohols react both as nucleophiles and electrophiles. 
Reason R: Alcohols react with active metals such as sodium, potassium and aluminum to yield corresponding alkoxides and liberate hydrogen. 
In the light of the above statements, choose the correct answer from the options given below:
The product (C) in the below mentioned reaction is: \(\text{CH}_3 - \text{CH}_2 - \text{CH}_2 - \text{Br} \xrightarrow{\text{KOH}_{(alc)} \Delta} A \xrightarrow{\text{HBr}} B \xrightarrow{\text{KOH}_{(alc)}\Delta} C\)
 
A species having carbon with sextet of electrons and can act as electrophile is called
The metals that are employed in the battery industries are
A. Fe 
B. Mn 
C. Ni 
D. Cr 
E. Cd 
Choose the correct answer from the options given below:
The compound that is white in color is
Identify the mixture that shows positive deviations from Raoult's Law
For the given reaction, choose the correct expression of \(K_c\)​ from the following: \(Fe_{(aq)}^{3+}​+SCN_{(aq)}^{−}​⇌(FeSCN)_{(aq)}^{2+}\)​
Give below are two statements:
Statement-I : Noble gases have very high boiling points. 
Statement-II: Noble gases are monoatomic gases. They are held together by strong dispersion forces. Because of this they are liquefied at very low temperature. Hence, they have very high boiling points. 
In the light of the above statements, choose the correct answer from the options given below.
$\text{The total number of molecules with zero dipole moment among CH}_4, \text{ BF}_3, \text{ H}_2\text{O, HF, NH}_3, \text{ CO}_2 \text{ and} \\ \text{SO}_2 \text{ is \_\_\_\_\_\_\_\_.}$
$\text{Standard enthalpy of vaporisation for CCl}_4 \text{ is 30.5 kJ mol}^{-1}. \text{ Heat required for vaporisation of } 284 \, \text{g of CCl}_4 \text{ at constant temperature is } \_\_\_\_ \, \text{kJ.} \\ \text{(Given molar mass in g mol}^{-1}\text{; C = 12, Cl = 35.5)}$
$\text{A constant current was passed through a solution of AuCl}_4^- \text{ ion between gold electrodes. After a} \\\text{period of 10.0 minutes, the increase in mass of cathode was 1.314 g. The total charge passed} \\$$\text{through the solution is \_\_\_\_\_\_\_\_} \times 10^{-2} \, \text{F.} \\$$\text{(Given atomic mass of Au = 197)}$
The half-life of radio isotopic bromine - 82 is 36 hours. The fraction which remains after one day is ___________ ×10–2.
(Given antilog 0.2006 = 1.587)
The total number of ‘Sigma’ and Pi bonds in 2 formylhex-4-enoic acid is ____.
A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is ___________ (Integer Answer)
(Given : Molar mass in g mol$^{-1}$ Ethyl alcohol : 46, water : 18)
Total number of aromatic compounds among the following compounds is _______.
aromatic compounds
The total number of carbon atoms present in tyrosine, an amino acid, is _______.
Total number of optically active compounds from the following is _______.
CH Compounds
Number of molecules having bond order 2 from the following molecule is ...................
$C_2, O_2, Be_2, Li_2, Ne_2, N_2, He_2$
$\Delta_{vap}H^\circ$ for water is $+40.49 \, \text{kJ mol}^{-1}$ at 1 bar and $100^\circ\text{C}$. Change in internal energy for this vaporisation under same condition is .............. kJ mol$^{-1}$. (Integer answer)
(Given R = 8.3 J K$^{-1}$ mol$^{-1}$)
Match List-I with List-II.
List-I
(Complex ion)		List-II
(Spin only magnetic moment in B.M.)
(A) [Cr(NH$_3$)$_6$]$^{3+}$(I) 4.90
(B) [NiCl$_4$]$^{2-}$(II) 3.87
(C) [CoF$_6$]$^{3-}$(III) 0.0
(D) [Ni(CN)$_4$]$^{2-}$(IV) 2.83

Choose the correct answer from the options given below:
Given below are two statements:
Statement (I) : Fusion of MnO$_2$ with KOH and an oxidising agent gives dark green K$_2$MnO$_4$.
Statement (II) : Manganate ion on electrolytic oxidation in alkaline medium gives permanganate ion.
In the light of the above statements, choose the correct answer from the options given below.
The reaction;$\frac{1}{2}H_{2(g)} + AgCl_{(s)} \rightarrow H^+_{(aq)} + Cl^-_{(aq)} + Ag_{(s)}$ occurs in which of the following galvanic cell:
Given below are two statements :
Statement (I) : Kjeldahl method is applicable to estimate nitrogen in pyridine.
Statement (II) : The nitrogen present in pyridine can easily be converted into ammonium sulphate in Kjeldahl method.
In the light of the above statements, choose the correct answer from the options given below.