List of top Chemistry Questions

In an oxidation-reduction reaction, what happens to the oxidation state of the central atom in \( \text{MnO}_4^- \) when it is reduced to \( \text{Mn}^{2+} \)?
In the reaction \( 2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2 \), what is the role of potassium iodide (KI) in this reaction?
What is the shape of the \( \text{ClO}_2^- \) ion according to VSEPR theory?
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).

0.01 mole of an organic compound (X) containing 10% hydrogen, on complete combustion, produced 0.9 g H₂O. Molar mass of (X) is ___________g mol\(^{-1}\).

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:
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.

Identify the coordination complexes

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?

Match List-I with List-II. 

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}

Given below are two statements: 
Statement (I): For a given shell, the total number of allowed orbitals is given by \( n^2 \). 
Statement (II): For any subshell, the spatial orientation of the orbitals is given by \( -l \) to \( +l \) values including zero. In the light of the above statements, choose the correct answer from the options given below:

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?
Consider the reaction: $$ X_2Y(g) \rightleftharpoons X_2(g) + \frac{1}{2} Y_2(g) $$ The equation representing the correct relationship between the degree of dissociation \( x \) of \( X_2Y(g) \) with its equilibrium constant \( K_p \) is: 

Given below are two statements: 
Statement (I): In the case of formaldehyde, \( K \) is about 2280, due to small substituents, hydration is faster. 
 
Statement (II): In the case of trichloroacetaldehyde, \( K \) is about 2000 due to the -I effect of Cl. 
 
In the light of the above statements, choose the correct answer from the options given below:

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 effect of temperature on the spontaneity of reactions are represented as:  Which of the following is correct?

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)