List of top Chemistry Questions asked in JEE Main

In which form does \(BeCl_{2}\) exist in the solid state, vapor state and high temperature?
(1) Polymeric, Dimeric, Monomeric
(2) Dimeric, Polymeric, Monomeric
(3) Monomeric, Dimeric, Polymeric
(4) Polymeric, Monomeric, Dimeric

Which one of the following elements will remain as liquid inside pure boiling water?

Ion having highest hydration enthalpy among the given alkaline earth metal ions is:

XeF$_4$ reacts with SbF$_5$ to form:
\[ [\text{XeF}_m]^{n+}[\text{SbF}_y]^{z-} \] What is $m+n+y+z$?
During the detection of Lead, the Formation of which of the following compounds is not used as a confirmatory test.
IUPAC name of the compound \(K_{3}[Co(C_{2}O_{4})_{3}]\) is
Consider the following:
  1. D.D.T.
  2. Aldrin
  3. Sodium arsenite
  4. Sodium chlorate
How many of these are pesticides?
Match the terms in Column-I with their description in Column-II and choose the correct option:
 Amino Acid Letter Code
(A).Alanine(P).N
(B).Asparagine(Q).A
(C).Aspartic acid(R).R
(D).Arginine(S).D
How many factors will contribute to a major role in covalent character of a compound.
  1. Polarising power of cation
  2. Polarisability of the anion
  3. Distortion caused by cation
  4. Polarisability of cation
Consider the reaction \(Cu^{2+} + X^- → Cu_2X_2 + X_2\).
X2 will be predominantly?
Read the following two statements
Statement I: Ionic radius of Li+ is greater than Mg++
Statement II: Lithium and magnesium can't form superoxide
Which of the following elements is most reactive?
Select the correct order of electronegativity of the elements: B, C, At, S
0.5 gm of an organic compound with 60%. Carbon produce ______ gm of \(CO_{2}\) upon complete combustion

Sulphur (S)-containing amino acids from the following are:
(a) Isoleucine
(b) Cysteine
(c) Lysine
(d) Methionine
(e) Glutamic acid

How many statements are correct:
  1. If there is no relation between rate constant and temperature, then activation energy is negative.
  2. If the activation energy is zero, rate constant is temperature independent.
  3. If rate constant increases with increase of temperature, activation energy is positive.
  4. If rate constant decreases with increase in temperature, activation energy is negative.
The pair of lanthanides will exceptionally high 3rd ionisation enthalpy than neighbouring elements:
Which of the following shows an incorrect method of refining?
What happens when lyophilic sol is added to lyophobic sol. prevention from coagulation precipitation emulsion electrophoresis
For the 1st order reactions, the ratio of t50% to t87.5% will be:
An organic compound on combustion gives 0.22 g of CO2 and 0.126 g of H2O. If the percentage of C in given organic compound is 40%, the percentage of H will be?
Radius of the 2nd orbit of He+ is r0. Radius of the 4th orbit of Be3+ is xr0. Find x.

Given below are two statements: one is labeled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): Acidic nature follows the order:

Reason (R): F is a better electron-withdrawing group than Cl
In the light of the above statements, write the detailed answer:

If the formula of borax is \(Na_2B_4Ox(OH)y.zH_2O\) , Find the value of x + y + z. 
In which of the following options the species changes from paramagnetic to diamagnetic and bond order increases.