List of top Chemistry Questions asked in JEE Main

The bond dissociation enthalpy of \( X_2 \) calculated from the given data is ---- kJ mol\(^{-1}\) (nearest integer). % Given Data: \[ M(s) + X(s) \rightarrow M^+(g) + X^-(g) \quad \Delta H_{\text{lattice}} = 800 \, \text{kJ/mol} \] \[ M(s) \rightarrow M(g) \quad \Delta H_{\text{sub}} = 100 \, \text{kJ/mol} \] \[ M(g) \rightarrow M^+(g) + e^-(g) \quad \Delta H_{\text{i}} = 500 \, \text{kJ/mol} \] \[ X(g) + e^-(g) \rightarrow X^-(g) \quad \Delta H_{\text{eg}} = -300 \, \text{kJ/mol} \] \[ M(s) + X_2(g) \rightarrow M^+X^-(s) \quad \Delta H_{\text{f}} = -400 \, \text{kJ/mol} \]

When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is ----- (nearest integer).

Given below are two statements about X-ray spectra of elements:
Statement (I):A plot of \(\sqrt {v}\) (v=frequency of X-rays emitted) vs atomic mass is a straight line.
Statement (II): A plot of v (v=frequency of X-rays emitted)} vs atomic number is a straight line.

Consider a binary solution of two volatile liquid components 1 and 2. \(x_1\) and \(y_1\) are the mole fractions of component 1 in the liquid and vapor phase, respectively. The slope and intercept of the linear plot of \( \frac{1}{x_1} \) vs \( \frac{1}{y_1} \) are given respectively as:

Identify the products [A] and [B] respectively in the following reaction:

pH of water is 7 at 25°C. If water is heated to 80°C, its pH will:

Given below are the atomic numbers of some group 14 elements. The atomic number of the element with the lowest melting point is:

Identify the coordination complexes in which the central metal ion has a \(d^4\) configuration.

Choose the correct answer from the options given below :

Match List-I with List-II.

Choose the correct answer from the options given below :

Which of the following graphs most appropriately represents a zero-order reaction?

The ascending order of relative rate of solvolysis of the following compounds is: \includegraphics[]{60.PNG} \begin{itemize} \item (A) Cyclohexyl bromide \item (B) Benzyl bromide \item (C) Phenylmethyl bromide \item (D) Allyl bromide \end{itemize}

When a non-volatile solute is added to the solvent, the vapour pressure of the solvent decreases by 10 mm of Hg. The mole fraction of the solute in the solution is 0.2. What would be the mole fraction of the solvent if the decrease in vapour pressure is 20 mm of Hg?

The alpha-helix and beta-pleated sheet structures of a protein are associated with its:

Standard electrode potentials for a few half-cells are mentioned below:

The standard enthalpy and standard entropy of decomposition of \( N_2O_4 \) to \( NO_2 \) are 55.0 kJ mol\(^{-1}\) and 175.0 J/mol respectively. The standard free energy change for this reaction at 25°C in J mol\(^{-1}\) is (Nearest integer)

Consider the following sequence of reactions to produce major product (A):

The molar mass of the product (A) is g mol−1. (Given molar mass in g mol−1 of C: 12,
H: 1, O: 16, Br: 80, N: 14, P: 31)

During "S" estimation, 160 mg of an organic compound gives 466 mg of barium sulphate. The percentage of Sulphur in the given compound is %.
(Given molar mass in g mol\(^{-1}\) of Ba: 137, S: 32, O: 16)

If 1 mM solution of ethylamine produces pH = 9, then the ionization constant (\(K_b\)) of ethylamine is \(10^{-x}\).

The value of x is (nearest integer).
The degree of ionization of ethylamine can be neglected with respect to unity.

Which of the following happens when NH\(_4\)OH is added gradually to the solution containing 1M A\(^{2+}\) and 1M B\(^{3+}\) ions? Given: K\(_{sp}\)[A(OH)\(_2\)] = 9 \(\times\) 10\(^\text{-10}\) and K\(_{sp}\)[B(OH)\(_3\)] = 27 \(\times\) 10\(^\text{-18}\) at 298 K.

What amount of bromine will be required to convert 2 g of phenol into 2, 4, 6-tribromophenol? (Given molar mass in g mol\(^{-1}\) of C, H, O, Br are 12, 1, 16, 80 respectively)

The complex that shows Facial - Meridional isomerism is:

The d-electronic configuration of an octahedral Co(II) complex having a magnetic moment of 3.95 BM is:

2.8 \( \times 10^{-3} \) mol of \( \text{CO}_2 \) is left after removing \( 10^{21} \) molecules from its ‘\( x \)’ mg sample. The mass of \( \text{CO}_2 \) taken initially is: Given: \( N_A = 6.02 \times 10^{23} \, \text{mol}^{-1} \)