List of top Chemistry Questions asked in JEE Main

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

A diatomic molecule has a dipole moment of $ 1.2 \, D $. If the bond distance is $ 1 \, \text{Å} $, then fractional charge on each atom is ______ $ \times 10^{-1} \, \text{esu} $.
(Given $ 1 \, D = 10^{-18} \, \text{esu cm} $)

Consider the following elements.

Which of the following is/are true about A',B',C'andD' ? A. Order of atomic radii: $ B' < A' < D' < C' $
B. Order of metallic character: $ B' < A' < D' < C' $
C. Size of the element: $ D' < C' < B' < A' $
D. Order of ionic radii: $ B^{+} < A^{+} < D^{+} < C^{+} $
Choose the correct answer from the options given below:

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

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

Given below are two statements:
Statement I: Group 13 trivalent halides get easily hydrolyzed by water due to their covalent nature.
Statement II: $ AlCl_3 $ upon hydrolysis in acidified aqueous solution forms octahedral $[Al(H_2O)_6]^{3+}$ ion.
In the light of the above statements, choose the correct answer from the options given below:

The fragrance of flowers is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in vapour phase. A suitable method for the extraction of these oils from the flowers is -

Which of the following is least ionic ?

Identify the name reaction

Choose the correct statements from the following:
A. All group 16 elements form oxides of general formula $ EO_2 $ and $ EO_3 $ where $ E = S, Se, Te, $ and Po. Both the types of oxides are acidic in nature.
B. TeO$_2$ is an oxidising agent while SO$_2$ is reducing in nature.
C. The reducing property decreases from H$_2$S to H$_2$Te down the group.
D. The ozone molecule contains five lone pairs of electrons.
Choose the correct answer from the options given below:

$ A_{(g)} \rightleftharpoons B_{(g)} + \frac{C}{2}_{(g)} $ The correct relationship between $ K_P $, $ \alpha $, and equilibrium pressure $ P $ 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:

The azo-dye (Y) formed in the following reactions is: Sulphanilic acid + NaNO$_2$ + CH$_3$COOH → X

Select the option with correct property -

Identify structure of 2,3-dibromo-1-phenylpentane.

Identify major product ‘P’ formed in the following reaction.

Given below are two statements:
Statement I: $ \text{S}_8 $ solid undergoes disproportionation reaction under alkaline conditions to form $ \text{S}^{2-} $ and $ \text{S}_2\text{O}_3^{2-} $.
Statement II: $ \text{ClO}_4^- $ can undergo disproportionation reaction under acidic condition.
In the light of the above statements, choose the most appropriate answer from the options given below:

Identify A and B in the following reaction sequence.

If $5$ moles of an ideal gas expands from $10$ L to a volume of $100$ L at $300k$ under isothermal and reversible condition then work, $W$, is $- x J$. The value of x is $(even \;n = 8.314 \;J \;K^{-1} mol^{-1})$

The electronic configuration of Einsteinium is :(Given atomic number of Einsteinium = 99)

Which of the following compounds will give silver mirror with ammoniacal silver nitrate?
(A) Formic acid
(B) Formaldehyde
(C) Benzaldehyde
(D) Acetone
Choose the correct answer from the options given below :

Match List I with List II

List-I	List-II
A. Melting point [K]	I. Tl > In > Ga > Al > B
B. Ionic Radius [M³/pm]	II. B > Tl > Al ≈ Ga ≈ In
C. Δ_iH₁ [kJ mol^-1]	III. Tl > In > Al > Ga > B
D. Atomic Radius [pm]	IV. B > Al > Tl > In > Ga

Choose the correct answer from the options given below:

Number of spectral lines obtained in He⁺ spectra, when an electron makes transition from fifth excited state to first excited state will be __________.

Match List I with List II

List-I (Element)	List-II (Electronic Configuration)
A. N	I. [Ar] 3d¹⁰ 4s² 4p⁵
B. S	II. [Ne] 3s² 3p⁴
C. Br	III. [He] 2s² 2p³
D. Kr	IV. [Ar] 3d¹⁰ 4s² 4p⁶

Choose the correct answer from the options given below: