List of top Chemistry Questions asked in JEE Main

A solution contains 0.25 moles of non-volatile solute dissolved in one mole of solvent. Then calculate the % vapor pressure of solution relative to the vapor pressure of pure solvent.

Which of the following pair of species have different Lewis structures? (A) \( \mathrm{SO_3^{2-}, CO_3^{2-}} \)
(B) \( \mathrm{O_2^{2-}, F_2} \)
(C) \( \mathrm{CN^- , CO} \)
(D) \( \mathrm{NH_3, H_3O^+} \)
(E) \( \mathrm{MnO_4^- , CrO_4^{2-}} \)

The pairs among $A = [SO_3^{2-}, CO_3^{2-}]$, $B = [O_2^-, F_2]$, $C = [CN^-, CO]$, $D = [NH_3, H_3O^+]$ and $E = [MnO_4^-, CrO_4^{2-}]$ that do not have similar Lewis dot structure are

Given below are two statements:
Statement I: [CoBr₄]²⁻ ion will absorb light of lower energy than [CoCl₄]²⁻ ion.
Statement II: In [CoBr₄]²⁻ ion, the energy separation between the two set of d-orbitals is more than [CoCl₄]²⁻ ion.
In the light of the above statements, choose the correct answer from the options given below :

Find out the statements which are not true.
A. Resonating structures with more covalent bonds and less charge separation are more stable.
B. In electromeric effect, an unsaturated system shows +E effect with nucleophile and –E effect with electrophile.
C. Inductive effect is responsible for high melting point, boiling point and dipole moment of polar compounds.
D. The greater the number of alkyl groups attached to the doubly bonded carbon atoms, higher is the heat of hydrogenation.
E. Stability of carbanion increases with increase in s-character of the carbon carrying negative charge.

The correct order of the rate of the reaction for the following reaction with respect to nucleophiles is :
\( CH_3Br + Nu^\ominus \rightarrow CH_3Nu + Br^\ominus \)

Given below are some of the statements about Mn and \( Mn_2O_7 \). Identify the correct statements.
A. Mn forms the oxide \( Mn_2O_7 \), in which Mn is in its highest oxidation state.
B. Oxygen stabilizes the Mn in higher oxidation states by forming multiple bonds with Mn.
C. \( Mn_2O_7 \) is an ionic oxide.
D. The structure of \( Mn_2O_7 \) consists of one bridged oxygen.
Choose the correct answer from the options given below :

Consider the following reaction:

The product \(Y\) formed is:

The oxidation state of chromium in the final product formed in the reaction between KI and acidified $K_2Cr_2O_7$ solution is:

19.5 g of fluoro acetic acid (molar mass = 78 g mol\(^{-1}\)) is dissolved in 500 g of water at 298 K. The depression in the freezing point of water was \(1^\circ C\). What is \(K_a\) of fluoro acetic acid? (For water, \(K_f = 1.86\, K\,kg\,mol^{-1}\)). Assume molarity and molality to have same values.

A monoatomic anion (A⁻) has 45 neutrons and 36 electrons. Atomic mass, group in the periodic table and physical state at room temperature of the element (A) respectively are

Shown below is the structure of methyl acetate with three different \(\alpha\), \(\beta\) and \(\gamma\) carbon–oxygen bonds. The correct order of bond lengths of these bonds is :}

\( \text{SF}_4 \) is isostructural with:

Which of the following statement is correct about Hoffmann’s bromamide degradation reaction?
(a) Alkyl amide do not react.
(b) Secondary amide do not form secondary amide.
(c) Ratio of NaOH and Br₂ is 4 : 2.
(d) Na₂CO₃, NaBr and H₂O also formed along with amine.

Product is:

Find total number of aromatic compounds from the given organic molecules.

Which of the following statement(s) are incorrect?

Statement-1: During fractional distillation, higher boiling point will condense first.
Statement-2: In fractionating column, one which has higher boiling point value will be more in concentration above the fractionating column.

Which of the following compounds give a positive neutral FeCl\(_3\) test?

How many dibromo products are possible for ‘B’ (including stereoisomer)?

Statement 1:
Boiling point order is in decreasing order due to decreasing Vanderwaal's forces.

Statement 2:
P-dichlorobenzene has more melting point value due to its symmetric structure than O-dichlorobenzene while it has less boiling point than O-dichlorobenzene.

Benzene reacts with CO/HCl/AlCl₃ and give 'P'.
Benzene reacts with CH₃-C-Cl / AlCl₃ to give 'Q'.
P and Q react with each other in presence of NaOH / H₂O give product Z. Find number of π e⁻ in product Z.