List of top Chemistry Questions asked in JEE Main

$\dot{ C } l + CH _4 \rightarrow A + B$. $A$ and $B$ in the above atmospheric reaction step are

The dark purple colour of $KMnO _4$ disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is :

During the denaturation of proteins, which of these structures will remain intact ?

The photochemical smog does not generally contain :

Choose the correct order of density of the alkali metals :

The compound(s) that is(are) removed as slag during the extraction of copper is : 

1. \(CaO\) 
2.  \(FeO\) 
3.  \(Al _2 O _3\) 
4.  \(ZnO\)
5.  \(NiO\) 
   Choose the correct answer from the options given below :

Given below are two statements :
Statement I: In polluted water values of both dissolved oxygen and BOD are very low.
Statement II: Eutrophication results in decrease in the amount of dissolved oxygen.
In the light of the above statements, choose the most appropriate answer from the options given below :

Which of the following reaction/s will not give \(p-\) aminoazobenzene?

(A) $HOCl + H _{2} O _{2} \rightarrow H _{3} O ^{+}+ Cl ^{-}+ O _{2}$
(B) $I _{2}+ H _{2} O _{2}+2 OH ^{-} \rightarrow 2 I ^{-}+2 H _{2} O + O _{2}$
Choose the correct option.

Which of the following equation depicts the oxidizing nature of $H _{2} O _{2} ?$

Which of the following are isostructural pairs? A. $SO _{4}^{2-}$ and $CrO _{4}^{2-}$ B. $SiCl _{4}$ and $TiCl _{4}$ C. $NH _{3}$ and $NO _{3}^{-}$ D. $BCl _{3}$ and $BrCl _{3}$ $BCl _{3}$ and $BrCl _{3}$

According to Bohr's atomic theory :- (A) Kinetic energy of electron is $\propto \frac{ Z ^{2}}{ n ^{2}}$. (B) The product of velocity (v) of electron and principal quantum number (n), 'vn' $\propto Z ^{2}$. (C) Frequency of revolution of electron in an orbit is $\propto \frac{ Z ^{3}}{ n ^{3}}$. (D) Coulombic force of attraction on the electron is $\propto \frac{ Z ^{3}}{ n ^{4}}$. Choose the most appropriate answer from the options given below:

The correct order of bond dissociation enthalpy of halogens is :

Out of the following, which type of interaction is responsible for the stabilisation of $\alpha$ -helix structure of proteins?

Calgon is used for water treatment. Which of the following statement is $NOT$ true about Calgon?

In Freundlich adsorption isotherm, slope of AB line is :

Complete combustion of $1.80 g$ of an oxygen containing compound $\left( C _{ x } H _{ y } O _{2}\right)$ gave $2.64 g$ of $CO _{2}$ and $1.08 g$ of $H _{2} O$. The percentage of oxygen in the organic compound is:

Given below are two statements : Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame. Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame. In the light of the above statements, choose the most appropriate answer from the options given below.

What is the major product formed by $HI$ on reaction with

According to molecular theory, the species among the following that does not exist is:

Statements about heavy water are given below A. Heavy water is used in exchange reactions for the study of reaction mechanisms B. Heavy water is prepared by exhaustive electrolysis of water C. Heavy water has higher boiling point than ordinary water D. Viscosity of $H _{2} O$ is greater than $D _{2} O$

Cast iron is used for the manufacture of :

The major product formed in the following reaction is : $CH _{3} CH = CHCH \left( CH _{3}\right)_{2} \stackrel{ HBr }{\longrightarrow}$

If enthalpy of atomisation for $Br_{2(I)}$ is $x \,kJ/mol$ and bond enthalpy for $Br_2$ is $y\, kj/mol$, the relation between them :

The IUPAC name of the complex $[Pt(NH_3)_2Cl(NH_2CH_3)]Cl$ is :