List of top Chemistry Questions asked in JEE Main

Number of compounds among the following which contain sulfur as a heteroatom is ___.
Compounds: Furan, Thiophene, Pyridine, Pyrrole, Cysteine, Tyrosine

The total number of correct statements, regarding the nucleic acids is_________.
A. RNA is regarded as the reserve of genetic information.
B. DNA molecule self-duplicates during cell division.
C. DNA synthesizes proteins in the cell.
D. The message for the synthesis of particular proteins is present in DNA.
E. Identical DNA strands are transferred to daughter cells.

From the vitamins $ A, \, B_1, \, B_6, \, B_{12}, \, C, \, D, \, E, \, \text{and} \, K $, the number of vitamins that can be stored in our body is ______.

\[ 2 \text{MnO}_4^{-} + b \text{I}^{-} + c \text{H}_2\text{O} \rightarrow x \text{I}_2 + y \text{MnO}_2 + z \text{OH}^{-} \]
If the above equation is balanced with integer coefficients, the value of $ z $ is $ \_\_\_\_\_\_ $.

1 mole of PbS is oxidised by “X” moles of O₃>to get “Y” moles of O2. X + Y = __________

Chlorine undergoes disproportionation in alkaline medium as shown below:
$a \, \text{Cl}_2(g) + b \, \text{OH}^-(\text{aq}) \rightarrow c \, \text{ClO}^-(\text{aq}) + d \, \text{Cl}^-(\text{aq}) + e \, \text{H}_2\text{O}(\text{l})$
The values of $ a $, $ b $, $ c $, and $ d $ in a balanced redox reaction are respectively:

In alkaline medium, $ \text{MnO}_4^- $ oxidizes $ \text{I}^- $ to:

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:
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:

Number of moles of $ H^+ $ ions required by 1 mole of $ MnO_4^- $ to oxidise oxalate ion to $ CO_2 $ is ____.

Total number of species from the following which can undergo disproportionation reaction _______.
$\text{H}_2\text{O}_2, \text{ClO}_3^-, \text{P}_4, \text{Cl}_2, \text{Ag}, \text{Cu}^{+1}, \text{F}_2, \text{NO}_2, \text{K}^+$

Thiosulphate reacts differently with iodine and bromine in the reaction given below:
$$ 2S_2O_3^{2-} + I_2 \rightarrow S_4O_6^{2-} + 2I^- $$ $$ S_2O_3^{2-} + 5Br_2 + 5H_2O \rightarrow 2SO_4^{2-} + 4Br^- + 10H^+ $$
Which of the following statements justifies the above dual behaviour of thiosulphate?

When $ \text{MnO}_2 $ and $ \text{H}_2\text{SO}_4 $ is added to a salt (A), the greenish yellow gas liberated as salt (A) is:

Only $ 2 \, \text{mL} $ of $ \text{KMnO}_4 $ solution of unknown molarity is required to reach the end point of a titration of $ 20 \, \text{mL} $ of oxalic acid ($ 2 \, \text{M} $) in acidic medium. The molarity of $ \text{KMnO}_4 $ solution should be ______ $ \text{M} $.

The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is _______. Ti²⁺, Cr²⁺ and V²⁺.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In aqueous solutions $ \text{Cr}^{2+} $ is reducing while $ \text{Mn}^{3+} $ is oxidising in nature.
Reason (R): Extra stability to half-filled electronic configuration is observed than incompletely filled electronic configuration.
In the light of the above statement, choose the most appropriate answer from the options given below:

Consider the following redox reaction:\[\text{MnO}_4^- + \text{H}^+ + \text{H}_2 \text{C}_2 \text{O}_4 \rightleftharpoons \text{Mn}^{2+} + \text{H}_2 \text{O} + \text{CO}_2\]The standard reduction potentials are given as below (E$_\text{red}$):\[E^\circ_{\text{MnO}_4^-/\text{Mn}^{2+}} = +1.51 \, \text{V}\]\[E^\circ_{\text{CO}_2/\text{H}_2 \text{C}_2 \text{O}_4} = -0.49 \, \text{V}\]If the equilibrium constant of the above reaction is given as $K_\text{eq} = 10^x$, then the value of (x = ________ ) (nearest integer).

Products for the below reaction are:

The products A and B formed in the following reaction scheme are respectively

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: H₂Te is more acidic than H₂S.

Reason R: Bond dissociation enthalpy of H₂Te is lower than H₂S.

In light of the above statements, choose the most appropriate from the options given below:

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.

Major product of the following reaction is