Skip to content
Login Register

CHEMISTRY

This category holds Chemistry practice questions spanning physical, organic and inorganic chemistry, including topics such as atomic structure, chemical bonding, reactions, equilibrium and periodic properties. Attempt the questions to test both your conceptual understanding and your numerical work, then review the answers before moving on.

45 questions

CHEMISTRY

A solution contains 5 g of glucose dissolved in 95 g of water. What is the mass percentage of glucose?

Given: A solution contains 5 g of glucose dissolved in 95 g of water. What is the mass percentage of glucose? These values define the system as per NCERT data. Formula: Total mass = 5 + 95 = 100 g. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Mass % = (5 / 100) × 100 = 5%. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Solutions, Topic: Concentration terms and colligative properties.

View Details
CHEMISTRY

The K_a of HF is 6.8 × 10⁻⁴. What is the pH of a 0.1 M HF solution?

Given: The K_a of HF is 6.8 × 10⁻⁴. What is the pH of a 0.1 M HF solution? These values define the system as per NCERT data. Formula: K_a = frac[H+][F-][HF] approx x²/0.1, 6.8 × 10⁻⁴= x²/0.1, x² = 6.8 × 10⁻⁵, x approx 8.25 × 10⁻³. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: pH = -log(8.25 × 10⁻³) approx 2.08 . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Solutions, Topic: Concentration terms and colligative properties.

View Details
CHEMISTRY

A first-order reaction has a rate constant of 0.0462 min^{-1 . What is the half-life in minutes?

Given: A first-order reaction has a rate constant of 0.0462 min^{-1 . What is the half-life in minutes? These values define the system as per NCERT data. Formula: t_{1/2 = 0.693/k = 0.693/0.0462 = 15 min .. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Substituting values like 1.2 × 10⁻⁵, 236 J kg⁻¹ K⁻¹, CH₃CH₂NH₂ etc. into the formula and simplifying step by step. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

View Details
CHEMISTRY

Calculate the boiling point elevation of a solution containing 6 g of urea ( NHâ‚‚CONHâ‚‚ ) in 100 g of water. ( K_b = 0

Given: Calculate the boiling point elevation of a solution containing 6 g of urea ( NH₂CONH₂ ) in 100 g of water. ( K_b = 0.52 K kg/mol, Molar mass of urea = 60 g/mol ) These values define the system as per NCERT data. Formula: Moles of urea = 6/60 = 0.1 mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Molality = 0.1/0.1 = 1 mol/kg . Δ T_b = 0.52 × 1 = 0.52 K . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

View Details
CHEMISTRY

For FeO(s) + CO(g) Fe(s) + COâ‚‚(g), K_p = 0.5 atm at 1000 K. If initial p_{CO = 1 atm, what is p_{COâ‚‚ at equilibrium?

Given: For FeO(s) + CO(g) Fe(s) + CO₂(g), K_p = 0.5 atm at 1000 K. If initial p_{CO = 1 atm, what is p_{CO₂ at equilibrium? These values define the system as per NCERT data. Formula: Let p_{CO₂ = x, p_{CO = 1 - x. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Solids are omitted. K_p = fracp_{CO₂p_{CO = x/1 - x = 0.5 . x = 0.5 - 0.5x, 1.5x = 0.5, x = 0.333 atm. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Thermodynamics, Equilibrium and Chemical Kinetics, Topic: Energetics, equilibrium constants and reaction rates.

View Details
CHEMISTRY

A zero-order reaction has a rate constant of 2.0 × 10⁻² mol L^{-1 min^{-1 . How long will it take for 0.5 M to reduc

Given: A zero-order reaction has a rate constant of 2.0 × 10⁻² mol L^{-1 min^{-1 . How long will it take for 0.5 M to reduce to 0.1 M? These values define the system as per NCERT data. Formula: t = frac[R]_0 - [R]k = frac0.5 - 0.12.0 × 10⁻²= 20 min .. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Substituting values like 1.2 × 10⁻⁵, 236 J kg⁻¹ K⁻¹, CH₃CH₂NH₂ etc. into the formula and simplifying step by step. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

View Details
CHEMISTRY

What is the molar conductivity at infinite dilution for CaCl₂ if the ionic molar conductivities of Ca²⁺ and Cl⁻ a

Given: What is the molar conductivity at infinite dilution for CaCl₂ if the ionic molar conductivities of Ca²⁺ and Cl⁻ are 119.0 S cm² mol⁻¹ and 76.3 S cm² mol⁻¹ respectively? These values define the system as per NCERT data. Formula: According to Kohlrausch’s law, Lambda_m⁰ = lambda_{Ca^{2+⁰ + 2lambda_{Cl^{-⁰. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Lambda_m⁰ = 119.0 + 2 × 76.3 = 119.0 + 152.6 = 271.6 S cm² mol^{-1 . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

View Details
CHEMISTRY

In the reaction 4NH₃ + 5O₂ -> 4NO + 6H₂O, how many grams of O₂ are required to react with 17 g of NH₃? (Atomic

Given: In the reaction 4NH₃ + 5O₂ -> 4NO + 6H₂O, how many grams of O₂ are required to react with 17 g of NH₃? (Atomic masses: N = 14, H = 1, O = 16) These values define the system as per NCERT data. Formula: Molar mass of NH₃ = 17 g/mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Moles of NH₃ = 17 / 17 = 1 mol. 4 mol NH₃ require 5 mol O₂. Moles of O₂ = (5 / 4) × 1 = 1.25 mol. Mass = 1.25 × 32 = 40 g. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

View Details
CHEMISTRY

A reaction has k = 1.0 × 10⁻³ s^{-1 at 27°C and E_a = 52 kJ mol^{-1 . What is the temperature (in °C) when k = 3.0

Given: A reaction has k = 1.0 × 10⁻³ s^{-1 at 27°C and E_a = 52 kJ mol^{-1 . What is the temperature (in °C) when k = 3.0 × 10⁻³ s^{-1 ? (R = 8.314 J/mol · K) These values define the system as per NCERT data. Formula: log frac3.0 × 10⁻³¹.0 × 10⁻³= 52000/2.303 × 8.314 ( T_2 - 300/300 T_2 ). This is the standard NCERT relation for this phenomenon. Substitution & Calculation: 0.477 = 2717.5 ( T_2 - 300/300 T_2 ), T_2 approx 316 K = 43 °C . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

View Details