List of top Chemistry Questions asked in JEE Main

Lowest oxidation number of an atom in a compound \( A_2B \) is -2. The number of electrons in its valence shell is:
Total number of deactivating groups in aromatic electrophilic substitution reaction among the following is
Chemical reaction

The number of molecules/ions having trigonal bipyramidal shape is:
\(\text{PF}_5, \, \text{BrF}_5, \, \text{PCl}_5, \, [\text{PtCl}_4]^{2-}, \, \text{BF}_3, \, \text{Fe(CO)}_5\)

The number of white coloured salts among the following is ___________.
(A) SrSO\(_4\), (B) Mg(NH\(_4\))PO\(_4\), (C) BaCrO\(_4\), (D) Mn(OH)\(_2\), (E) PbSO\(_4\), (F) PbCrO\(_4\), (G) AgBr, (H) PbI\(_2\), (I) CaC\(_2\)O\(_4\),(J) [Fe(OH)\(_2\)(CH\(_3\)COO)\(_2\)]

Number of optical isomers possible for 2 – chlorobutane ________
Given below are two statements:
Statement (I) : The NH2 group in Aniline is ortho and para directing and a powerful activating group.
Statement (II) : Aniline does not undergo Friedel- Craft’s reaction (alkylation and acylation). In the light of the above statements
Choose the most appropriate answer from the options given below :
Choose the correct option for free expansion of an ideal gas under adiabatic condition from the following :
Given below are two statements :
Statement (I) : Potassium hydrogen phthalate is a primary standard for standardisation of sodium hydroxide solution.
Statement (II) : In this titration phenolphthalein can be used as indicator.
In the light of the above statements, choose the most appropriate answer from the options given below:
In Kjeldahl’s method for estimation of nitrogen, CuSO\(_4\) acts as:
We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentration 0.1 M, 0.01M & 0.001 M, respectively. The value of vant’ Haft factor (i) for these solutions will be in the order.
Arrange the bonds in order of increasing ionic character in the molecules. LiF, K\(_2\)O, N\(_2\), SO\(_2\), and ClF\(_3\).
Ionic reactions with organic compounds proceed through:
(A) Homolytic bond cleavage
(B) Heterolytic bond cleavage
(C) Free radical formation
(D) Primary free radical
(E) Secondary free radical
Choose the correct answer from the options given below:
Which of the following complex is homoleptic?
Given below are two statements:
Statement (I) : Aminobenzene and aniline are same organic compounds.
Statement (II) : Aminobenzene and aniline are different organic compounds.
In the light of the above statements, choose the most appropriate answer from the options given below:
Identify A and B in the following sequence of reaction.
Reaction
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : PH3 has lower boiling point than NH3.
Reason (R) : In liquid state NH3 molecules are associated through vander waal’s forces, but PH3 molecules are associated through hydrogen bonding.
In the light of the above statements.
Choose the most appropriate answer from the options given below:
Given below are two statements:
Statement (I): A solution of \([Ni(H_2O)_6]^{2+}\) is green in color.
Statement (II): A solution of \([Ni(CN)_4]^{2-}\) is colorless.  
In the light of the above statements, choose the most appropriate answer from the options given below.
According to the wave-particle duality of matter by de-Broglie, which of the following graph plot presents most appropriate relationship between wavelength of electron () and momentum of electron (p)?
In case of isoelectronic species the size of F– , Ne and Na+ is affected by:
Which of the following reactions are disproportionation reactions?
\(\text{(A) } \text{Cu}^+ \rightarrow \text{Cu}^{2+} + \text{Cu}\)
\(\text{(B) } 3\text{MnO}_4^{2-} + 4\text{H}^+ \rightarrow 2\text{MnO}_4^- + \text{MnO}_2 + 2\text{H}_2\text{O}\)
\(\text{(C) } 2\text{KMnO}_4 \rightarrow \text{K}_2\text{MnO}_4 + \text{MnO}_2 + \text{O}_2\)
\(\text{(D) } 2\text{MnO}_4^- + 3\text{Mn}^{2+} + 2\text{H}_2\text{O} \rightarrow 5\text{MnO}_2 + 4\text{H}^+\)
Choose the correct answer from the options given below.
In acidic medium, \( K_2Cr_2O_7 \) shows oxidizing action as represented in the half-reaction: \(Cr_2O_7^{2-} + XH^+ + Ye^- \rightarrow 2A + ZH_2O\)
\( X \), \( Y \), \( Z \), and \( A \) are respectively:
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Haloalkanes react with KCN to form alkyl cyanides as a main product while with AgCN form isocyanide as the main product.
Reason (R) : KCN and AgCN both are highly ionic compounds. In the light of the above statement
Choose the most appropriate answer from the options given below:
If one strand of a DNA has the sequence ATGCTTCA, sequence of the bases in complementary strand is:
From the given list, the number of compounds with +4 oxidation state of Sulphur_____.
\(SO_3​, H_2​SO_3​, SOCl_2​, SF_4​, BaSO_4​, H_2​S_2​O_7\)​.
The number of electrons present in all the completely filled subshells having n=4 and s=+½​ is _____. (Where n = principal quantum number and s = spin quantum number).