List of top Chemistry Questions asked in JEE Main

Select the option with correct property -

In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product is (+)_______.

The correct order of reactivity in electrophilic substitution reaction of the following compounds is :

Given below are two statements:
Statement I: Aniline reacts with con. \( H_2SO_4 \) followed by heating at 453–473 K gives p-aminobenzene sulphonic acid, which gives blood red colour in the 'Lassaigne's test'.
Statement II: In Friedel-Craft's alkylation and acylation reactions, aniline forms salt with the \( AlCl_3 \) catalyst. Due to this, nitrogen of aniline acquires a positive charge and acts as a deactivating group.
In the light of the above statements, choose the correct answer from the options given below:

r =k[A] for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% decomposition of A is ______ minutes.

The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19) are

Choose the correct statements from the following:
A. \( Mn_2O_7 \) is an oil at room temperature
B. \( V_2O_4 \) reacts with acid to give \( VO_2^{2+} \)
C. \( CrO \) is a basic oxide
D. \( V_2O_5 \) does not react with acid
Choose the correct answer from the options given below:

The emf of cell Tl$\vert^{Tl^+}_{_{(0.001M)}}\vert^{Cu^{2+}}_{_{(0.01M)}}$Cu is 0.83 V at 298 K. It could be increased by:

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) : A Buffer solution is the mixture of a salt and an acid or a base mixed in any particular quantities.
Statement (II) : Blood is naturally occurring buffer solution whose pH is maintained by $H_2CO_3/HCO_3^-$ concentrations.
In the light of the above statements, choose the correct answer from the options given below.

Two moles of benzaldehyde and one mole of acetone under alkaline conditions using aqueous NaOH after heating gives $x$ as the major product. The number of $\pi$ bonds in the product $x$ is ................

Number of molecules having bond order 2 from the following molecule is ...................
$C_2, O_2, Be_2, Li_2, Ne_2, N_2, He_2$

Given below are two statements:
Statement (I) : All the following compounds react with p-toluenesulfonyl chloride.
$C_6H_5NH_2 \quad      (C_6H_5)_2NH                \quad (C_6H_5)_3N$
Statement (II) : Their products in the above reaction are soluble in aqueous NaOH.
In the light of the above statements, choose the correct answer 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: The stability order of \(+1\) oxidation state of Ga, In, and Tl is \( \text{Ga}<\text{In}<\text{Tl} \).
Reason R: The inert pair effect stabilizes the lower oxidation state down the group.
In the light of the above statements, choose the correct answer from the options given below:

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.

Combustion of glucose (\(C_6H_{12}O_6\)) produces \(CO_2\) and water. The amount of oxygen (in g) required for the complete combustion of \(900 \, \text{g}\) of glucose is:
\([ \text{Molar mass of glucose in g mol}^{-1} = 180 ]\)

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.

Match List-I with List-II.

List-I (Name of the test)	List-II (Reaction sequence involved) [M is metal]
(A) Borax bead test	I
(B) Charcoal cavity test	II
(C) Cobalt nitrate test	III
(D) Flame test	IV

Choose the correct answer from the options given below:

$\Delta_{vap}H^\circ$ 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$^{-1}$)

Wavenumber for a radiation having $5800 \, \mathring{A}$ wavelength is $x \times 10 \, \text{cm}^{-1}$. The value of $x$ is _________

Total number of aromatic compounds among the following compounds is _______.

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:

Total number of optically active compounds from the following is _______.

Which among the following compounds will undergo fastest \(S_N2\) reaction?

Identify the correct statements about p-block elements and their compounds.
(A) Non metals have higher electronegativity than metals.
(B) Non metals have lower ionisation enthalpy than metals.
(C) Compounds formed between highly reactive nonmetals and highly reactive metals are generally ionic.
(D) The non-metal oxides are generally basic in nature.
(E) The metal oxides are generally acidic or neutral in nature.