CBSE Class 12 Chemistry Important Questions

1. What is the difference between physical and chemical changes?

Answer: Physical changes affect the form or appearance of a substance without altering its chemical composition, while chemical changes result in the formation of new substances with different properties.

2. Explain the concept of equilibrium in chemical reactions.

Answer: Chemical equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction, leading to constant concentrations of reactants and products over time.

3. What are colligative properties? Provide examples.

Answer: Colligative properties depend on the number of solute particles in a solution rather than their identity. Examples include vapour pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.

4. Describe the concept of hybridization and its types.

Answer: Hybridization is the mixing of atomic orbitals to form new hybrid orbitals for bonding. Types include sp, sp², sp³, dsp², and d²sp³, each corresponding to different molecular geometries.

5. What is the difference between ionic and covalent bonds?

Answer: Ionic bonds form through the transfer of electrons from one atom to another, resulting in charged ions, while covalent bonds involve the sharing of electrons between atoms.

6. Explain the significance of the periodic table trends, such as atomic radius and electronegativity.

Answer: Atomic radius generally decreases across a period and increases down a group, while electronegativity increases across a period and decreases down a group. These trends help predict element behaviour in reactions.

7. What are isomers? Differentiate between structural and stereoisomers.

Answer: Isomers are compounds with the same molecular formula but different structures. Structural isomers differ in the connectivity of atoms, while stereoisomers have the same connectivity but differ in spatial arrangement.

8. Define pH and its significance in chemistry.

Answer: pH is a measure of the acidity or basicity of a solution, defined as the negative logarithm of the hydrogen ion concentration. It is crucial for understanding chemical reactions in solutions, including acid-base reactions.

9. What are the different types of chemical reactions? Provide examples.

Answer: Major types include:

• Synthesis: A + B → AB

• Decomposition: AB → A + B

• Single Replacement: A + BC → AC + B

• Double Replacement: AB + CD → AD + CB

• Combustion: Hydrocarbon + O₂ → CO₂ + H₂O

10. What is the role of catalysts in chemical reactions?

Answer: Catalysts increase the rate of a chemical reaction by lowering the activation energy, allowing the reaction to proceed more quickly without being consumed in the process.

Here are some important questions for Class 12 Chemistry. For better understanding of each chapter, please go through the Chapter-wise Important Questions table. This resource will assist you in understanding the key concepts and important questions in each chapter and preparing effectively for your exams.

How does Class 12 Chemistry Important Questions Help you with Exams?

• Important questions highlight key topics and concepts that are frequently tested, allowing students to focus their study efforts effectively on the most relevant material.

• By practicing important questions, students can deepen their comprehension of complex concepts, which is essential for understanding the subject.

• Familiarity with important questions helps students understand the format and style of exam questions, reducing anxiety and building confidence during tests.

• These questions serve as a concise revision tool, helping students quickly recall critical information and reinforce their learning just before exams.

• Working through important questions allows students to identify topics they find challenging, enabling them to allocate more time and resources to those areas.

• Important questions often require students to apply their knowledge to solve problems, improving their analytical and problem-solving skills, which are vital for success in Chemistry.

Focusing on important questions in Class 12 Chemistry plays a vital role in exam preparation. These questions not only help students identify and understand key concepts but also enhance their problem-solving and critical-thinking skills. By practising these targeted questions, students can improve their confidence, manage their time effectively, and pinpoint areas that require further attention. Ultimately, this strategic approach to studying equips students with the tools they need to excel in their exams, making the learning process more efficient and effective. 

Additional Study Materials for Class 12 Chemistry