List of top Chemistry Questions asked in JEE Main

Molality of an aqueous solution of urea is 4.44 m. Mole fraction of urea in solution is x × 10^–3. Value of x is _______. (integer answer)

A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is ___________ (Integer Answer)
(Given : Molar mass in g mol$^{-1}$ Ethyl alcohol : 46, water : 18)

Two moles of benzaldehyde and one mole of acetone under alkaline conditions using aqueous NaOH after heating gives $x$ as the major product. The number of $\pi$ bonds in the product $x$ is ................

Match List-I with List-II.

List-I (Complex ion)	List-II (Spin only magnetic moment in B.M.)
(A) [Cr(NH$_3$)$_6$]$^{3+}$	(I) 4.90
(B) [NiCl$_4$]$^{2-}$	(II) 3.87
(C) [CoF$_6$]$^{3-}$	(III) 0.0
(D) [Ni(CN)$_4$]$^{2-}$	(IV) 2.83

Choose the correct answer from the options given below:

The correct sequence of acidic strength of the following aliphatic acids in their decreasing order is: $CH_3CH_2COOH$, $CH_3COOH$, $CH_3CH_2CH_2COOH$, $HCOOH$

Given below are two statements:
Statement (I) : A Buffer solution is the mixture of a salt and an acid or a base mixed in any particular quantities.
Statement (II) : Blood is naturally occurring buffer solution whose pH is maintained by $H_2CO_3/HCO_3^-$ concentrations.
In the light of the above statements, choose the correct answer from the options given below.

The equilibrium constant for the reaction
\( \text{SO}_3 \, (g) \rightleftharpoons \text{SO}_2 \, (g) + \frac{1}{2} \text{O}_2 \, (g) \)
is \( K_C = 4.9 \times 10^{-2} \). The value of \( K_C \) for the reaction given below is
\( 2 \text{SO}_2 \, (g) + \text{O}_2 \, (g) \rightleftharpoons 2 \text{SO}_3 \, (g) \) is

Number of amine compounds from the following giving solids which are soluble in NaOH upon reaction with Hinsberg's reagent is _____.

The incorrect statement regarding the given structure is

The number of optical isomers in following compound is : _____.

In the given compound, the number of 2° carbon atom/s is _____.

Among the following halogens \(F_2, \, Cl_2, \, Br_2, \, \text{and} \, I_2\)
Which can undergo disproportionation reaction?

Match List-I with List-II.

List-I (Molecule)	List-II (Shape)
(A) \(NH_3\)	(I) Square pyramid
(B) \(BrF_5\)	(II) Tetrahedral
(C) \(PCL_5\)	(III) Trigonal pyramidal
(D) \(CH_4\)	(IV) Trigonal bipyramidal

Choose the correct answer from the options given below:

Number of molecules from the following which are exceptions to octet rule is ____.
\(\text{CO}_2, \, \text{NO}_2, \, \text{H}_2\text{SO}_4, \, \text{BF}_3, \, \text{CH}_4, \, \text{SiF}_4, \, \text{ClO}_2, \, \text{PCl}_5, \, \text{BeF}_2, \, \text{C}_2\text{H}_6, \, \text{CHCl}_3, \, \text{CBr}_4\)

For the given hypothetical reactions, the equilibrium constants are as follows:
\[ X \rightleftharpoons Y; \, K_1 = 1.0 \]
\[ Y \rightleftharpoons Z; \, K_2 = 2.0 \]
\[ Z \rightleftharpoons W; \, K_3 = 4.0 \]
The equilibrium constant for the reaction
\[ X \rightleftharpoons W\]
is:

If 279 g of aniline is reacted with one equivalent of benzenediazonium chloride, the mximum amount of aniline yellow formed will be _____ g. (nearest integer)
(consider complete conversion)

Consider the following reaction
\[A + B \rightarrow C\]
The time taken for A to become 1/4th of its initial concentration is twice the time taken to become 1/2 of the same. Also, when the change of concentration of B is plotted against time, the resulting graph gives a straight line with a negative slope and a positive intercept on the concentration axis.
The overall order of the reaction is ____.

Number of complexes with even number of electrons in \(t_{2g}\) orbitals is: \[[\text{Fe(H}_2\text{O)}_6]^{2+}, \, [\text{Co(H}_2\text{O)}_6]^{2+}, \, [\text{Co(H}_2\text{O)}_6]^{3+}, \, [\text{Cu(H}_2\text{O)}_6]^{2+}, \, [\text{Cr(H}_2\text{O)}_6]^{2+}\]

Major product B of the following reaction has ____ \(\pi\)-bond.

The 'spin only' magnetic moment value of \(MO_4^{2-}\) is ____ \(\text{BM}\). (Where \(M\) is a metal having least metallic radii among \(\text{Sc, Ti, V, Cr, Mn, Zn}\)). \([ \text{Given atomic number: Sc = 21, Ti = 22, V = 23, Cr = 24, Mn = 25, Zn = 30} ]\)

A hypothetical electromagnetic wave is show below.

The frequency of the wave is x × 10¹⁹ Hz. x = ______ (nearest integer)

Consider the figure provided. 1 mol of an ideal gas is kept in a cylinder, fitted with a piston, at the position A, at \(18^\circ \text{C}\). If the piston is moved to position B, keeping the temperature unchanged, then 'x' \(\text{L atm}\) work is done in this reversible process. \(x =\) ______ \(\text{L atm}\). (nearest integer)
\([ \text{Given: Absolute temperature} = ^\circ \text{C} + 273.15, \, R = 0.08206 \, \text{L atm mol}^{-1} \text{K}^{-1} ]\)

Identify the product (P) in the following reaction:

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?

An octahedral complex with the formula \(\text{CoCl}_3n\text{NH}_3\) upon reaction with excess of \(\text{AgNO}_3\) solution gives 2 moles of \(\text{AgCl}\). Consider the oxidation state of Co in the complex is \(x\). The value of "x + n" is ______.