List of top Chemistry Questions asked in JEE Main

It has been found that for a chemical reaction with rise in temperature by 9 K the rate constant gets doubled. Assuming a reaction to be occurring at 300 K, the value of activation energy is found to be _________kJ mol–1. [nearest integer] (Given ln10 = 2.3, R = 8.3 J K–1 mol–1, log 2 = 0.30)
The complete combustion of 0.492 g of an organic compound containing ‘C’, ‘H’ and ‘O’ gives 0.793 g of CO2 and 0.442 g of H2O. The percentage of oxygen composition in the organic compound is_____.[nearest integer]
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. 
Assertion A: Permanganate titrations are not performed in presence of hydrochloric acid. 
Reason R: Chlorine is formed as a consequence of oxidation of hydrochloric acid. 
In the light of the above statements, choose the correct answer from the options given below.
Given below are two statements.
Statement I: Iron (III) catalyst, acidified \(K_2Cr_2O_7\) and neutral \(KMnO_4\) have the ability to oxidise \(I^–\) to \(I_2\) independently.
Statement II: Manganate ion is paramagnetic in nature and involves \(pπ – pπ\) bonding.
In the light of the above statements, choose the correct answer from the options given below.
Which of the following compounds is an example of hypnotic drug?

In the given conversion the compound A is:

In a solid AB, A atoms are in ccp arrangement and B atoms occupy all the octahedral sites. If two atoms from the opposite faces are removed, then the resultant stoichiometry of the compound is AxBy. The value of x is _____. [nearest integer]
\(120 \;g\) of an organic compound that contains only carbon and hydrogen gives \(330\) \(g\) of \(CO_2\) and \(270\) \(g\) of water on complete combustion. The percentage of carbon and hydrogen, respectively are
Amongst baking soda, caustic soda and washing soda, carbonate anion is present in
The oxide which contains an odd electron at the nitrogen atom is
The correct decreasing order for metallic character is
In a cell, the following reactions take place
\(Fe^{2+} → Fe^{3+} + e^-\)
\(E°_{Fe^{3+}/Fe^{2+}} = 0.77\ V\)
\(2I^- → I_2 + 2e^-\)
\(E_{I_2/I^-} = 0.54\ V\)
The standard electrode potential for the spontaneous reaction in the cell is \(x×10^{–2} V\) at \(208\ K\). The value of \(x\) is _______. (Nearest Integer)
A 42.12% (w, v) solution of NaCl causes precipitation of a certain sol in 10 hours. The coagulating value of NaCl for the sol is
[Given : Molar mass : Na = 23.0 g mol–1; Cl = 35.5 g mol–1]

Catalyst A reduces the activation energy for a reaction by 10 kJ mol–1 at 300 K. 
The ratio of rate constants,
\(\frac{Κ′ , Catalysed}{Κ,Uncatalysed}\)
is ex. The value of x is ____.[nearest integer]
[Assume that the pre-exponential factor is same in both the cases Given R = 8.31 J K–1 mol–1]

The number of statement(s) correct from the following for Copper (at. no. 29) is/are ______.

  1. Cu(II) complexes are always paramagnetic
  2. Cu(I) complexes are generally colourless
  3. Cu(I) is easily oxidized
  4. In Fehling solution, the active reagent has Cu(I)
Which among the following pairs of the structures will give different products onozonolysis? (Consider the double bonds in the structures are rigid and not delocalized)
The incorrect statement is
The acid that is believed to be mainly responsible for the damage of Taj Mahal is

With respect to the following reaction, consider the given statements:

Fig








(A) o-Nitroaniline and p-nitroaniline are the predominant products.
(B) p-Nitroaniline and m-nitroaniline are the predominant products.
(C) HNO3 acts as an acid.
(D) H2SO4 acts as an acid.
Choose the correct option.

Which of the following statements are correct?
  1. The electronic configuration of Cr is [Ar] 3d54s1.
  2. The magnetic quantum number may have a negative value.
  3. In the ground state of an atom, the orbitals are filled in order of their increasing energies.
  4. The total number of nodes are given by n – 2.
Choose the most appropriate answer from the options given below :
Match List I with List II
 List I (polymer) List-II (Nature)
A.
 
A.
I.
Thermosetting polymer
B.
B.
II.
Fibers
C.
C.
III.
Elastomer
D.
D.
IV.Thermoplastic polymer
Choose the correct answer from the options given below:
The correct decreasing order of energy for the orbitals having, following set of quantum numbers:
(A) n = 3, l = 0, m = 0
(B) n = 4, l = 0, m = 0
(C) n = 3, l = 1, m = 0
(D) n = 3, l = 2, m = 1
Ionic radii of cation A+ and anion B– are 102 and 181 pm, respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for B–. A+ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is _____pm. (Nearest integer)

The number of molecules(s) or ions(s) from the following having non-planar structure is ____.
\(NO^-_3, H_2O_2, BF_3, PCl_3, XeF_4, SF_4, XeO_3, PH^+_4, SO3,[Al(OH)_4]^-\)

The products obtained from a reaction of hydrogen peroxide and acidified potassium permanganate are