List of top Chemistry Questions asked in JEE Main

Identify the incorrect statements.

Correct statements from the following are:
A. Nitrogen in oxidation states from \(+1\) to \(+4\) disproportionates in acid medium.
B. Nitrogen has the ability to form \(d\pi - p\pi\) multiple bonds with itself and other elements with small size and high electronegativity.
C. N-N single bond is stronger than P-P single bond.
D. Nitrogen has highest density in its group due to small size.
E. The maximum covalency of nitrogen is four since it has only four valence orbitals for bonding.

\(M_3A_2\) is a sparingly soluble salt of molar mass \(y \text{ g mol}^{-1}\) and solubility \(x \text{ g L}^{-1}\). The ratio of the molar concentration of the anion (\(A^{3-}\)) to the solubility product (\(K_{sp}\)) of the salt is:

Which of the following is NOT a physical or chemical characteristic of interstitial compounds?

Given below are two statements:
Statement I: On the basis of inductive effect, the order of stability of alkyl carbanions is \(CH_3^->CH_3-CH_2^->(CH_3)_2CH^->(CH_3)_3C^-\).
Statement II: Allyl and benzyl carbanions are more stabilised by inductive effect and not by resonance effect.

"P" is a hydrocarbon of molecular formula:- \(C_8H_{14}\). On ozonolysis, "P" forms "Q". "Q" on treatment with alkali under reflux condition produces "R", which on treatment with \(I_2 / NaOH\) gives a yellow precipitate. Acidification of the solution gives "S". The structure of "S" is given below:-}

Identify the correct statements from the following :}
A. Heisenberg uncertainty principle is applicable to electrons.
B. The size of \(2p_x\) orbital is less than the size of \(3p_x\) orbital.
C. The energy of \(2s\) orbital of H atom is equal to the energy of \(2s\) orbital of Li.
D. The electronic configuration of Cr is \([Ar] 3d^5 4s^1\)

Given below are two statements:
Statement I: Each electron in \(e_g\) orbitals destabilizes the orbitals by \(+0.6 \Delta_o\) and each electron in the \(t_{2g}\) orbitals stabilizes the orbitals by \(-0.4 \Delta_o\) in an octahedral field on the basis of crystal field theory.
Statement II: All the d-orbitals of the transition metals have the same energy in their free atomic state but when a complex is formed the ligands destroy the degeneracy of these orbitals on the basis of crystal field theory.

Arrange the following resultant mixtures in increasing order of their pH values}
A. \(10 \text{ mL } 0.2 \text{ M Ca(OH)}_2 + 25 \text{ mL } 0.1 \text{ M HCl}\)
B. \(10 \text{ mL } 0.01 \text{ M H}_2\text{SO}_4 + 10 \text{ mL } 0.01 \text{ M Ca(OH)}_2\)
C. \(10 \text{ mL } 0.1 \text{ M H}_2\text{SO}_4 + 10 \text{ mL } 0.1 \text{ M KOH}\)

How many grams of residue is obtained by heating \(2.76 \text{ g}\) of silver carbonate? (Given : Molar mass of C, O and Ag are 12, 16 and \(108 \text{ g mol}^{-1}\) respectively)

Consider compounds A, B and C with following structural formulae
\(A = CH_3 - CH_2 - CH_2 - CH_2 - CH_2 - OH\)
\(B = CH_2 = CH - CH_2 - CH_2 - CH_3\)
\(C = HO - CH_2 - CH_2 - CH(OH) - CH_3\)
For the conversion of B from A, reagent (D) required is ____ and structural formula of product (E) obtained when C undergoes same reaction using excess reagent (D) is ____.

Benzyl isocyanide can be obtained from}

One mole of phenol is treated with dilute \(HNO_3\) at \(298 \text{ K}\) to give a mixture of products. The mixture is separated by steam distillation. The steam volatile compound (X) is separated. The increase in percentage of oxygen in (X) with respect to phenol is ____ \(\times 10^{-1}\) %.
(Given molar mass in \(\text{g mol}^{-1}\) H:1, C:12, N:14, O:16)}

Given below are two statements:
Statement I: The correct order of electronegativity of fluorine, oxygen and nitrogen is \(F>O>N\).
Statement II: The oxidation state of oxygen in \(OF_2\) is \(+2\) and in \(Na_2O\) is \(-2\).

Given below are two statements:
Statement I: Sodium dichromate and potassium dichromate are classified as primary standards in titrimetric analysis.
Statement II: Phenolphthalein is a weak base, therefore it dissociates in acidic medium.

For the following Friedel Craft's alkylation reaction, which of the statements are correct?}

A. Major product is n-propyl benzene.
B. iso-propyl carbocation intermediate is also generated.
C. Multiple substitution is inevitable.
D. Introducing electron-donating substituent on benzene will not produce any alkyl benzene.

Arrange the following atomic orbitals of multi electron atoms in order of increasing energy.
A. \(n=3, l=2, m=+1\)
B. \(n=4, l=0, m=0\)
C. \(n=6, l=1, m=0\)
D. \(n=5, l=1, m=+1\)
E. \(n=2, l=1, m=+1\)

What is the mole fraction of water in \(10%\) by weight (w/w) of aqueous urea solution? [Given: Molar mass of H, O, C and N are 1, 16, 12 and \(14 \text{ g mol}^{-1}\) respectively.]

If the half life of a first order reaction is \(6.93 \text{ minutes}\) then the time required for completion of \(99 %\) of the reaction will be ____ minutes.
(Given : \(\log 2 = 0.3010\))}

The values of pressure equilibrium constant recorded at different temperatures for the following equilibrium reaction have been given below:
\(A(g) \rightleftharpoons B(g) + C(g)\)}

The magnitude of \(\frac{\Delta H^\circ}{R}\) calculated from the above data is ____. (Nearest integer)}

In an estimation of sulphur by Carius method \(0.2 \text{ g}\) of the substance gave \(0.6 \text{ g}\) of \(BaSO_4\). The percentage of sulphur in the substance is ____ %.
(Given molar mass in \(\text{g mol}^{-1}\) S : 32, \(BaSO_4 : 231\))}

The major product of which of the following reaction is not obtained by rearrangement reaction?}

Bromine trifluoride autoionizes to form BrF$_2^+$ and BrF$_4^-$. The shapes of the cation and anion are respectively ________, and ________

‘x’ is the product which is obtained from benzene by reacting it with carbon monoxide and hydrogen chloride in the presence of cuprous chloride. ‘y’ is the major product obtained from the benzene by reacting it with ethanoyl chloride in the presence of anhydrous AlCl$_3$. Product (major) obtained by heating x and y in the presence of alkali is z. Total number of $\pi$ (pi) electrons in z is _______.

Match List-I with List-II.