Comprehensive NCERT Solutions for Class 12 Chemistry Chapter 2

Get expert NCERT solutions for Class 12 Chemistry Chapter 2. Access detailed, step-by-step answers to boost your understanding and ace your exams. Free PDF available!

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Master Class 12 Chemistry Chapter 2 with expert-curated NCERT solutions. This chapter covers essential concepts like electrochemistry, galvanic cells, and electrolysis. Strengthen your understanding with step-by-step solutions designed for CBSE exams. Download the free PDF to enhance your preparation and score high in your board exams!

Detailed NCERT Solutions for Class 12 Chemistry Chapter 2 – Questions & Answers

Electrochemistry, covered in Chapter 2 of Class 12 Chemistry NCERT, is a crucial topic that explores the relationship between electrical energy and chemical changes. Below are 50 sample questions and answers, carefully curated to help students understand key concepts.

Sample Questions & Answers for Chemistry Class 12 NCERT Solutions Chapter 2

What is electrochemistry?
Electrochemistry is the branch of chemistry that deals with the study of chemical processes that involve the movement of electrons, resulting in the conversion of chemical energy into electrical energy and vice versa.

Define a galvanic cell.
A galvanic cell is an electrochemical cell that generates electrical energy from spontaneous redox reactions occurring within it. It consists of two electrodes immersed in electrolyte solutions, connected by a salt bridge.

What is the function of a salt bridge in a galvanic cell?
A salt bridge maintains electrical neutrality by allowing the flow of ions between two half-cells, preventing charge buildup and enabling a continuous redox reaction.

What is an electrode potential?
Electrode potential is the measure of the tendency of an electrode to gain or lose electrons when it is in contact with its ion solution. It is measured in volts.

Differentiate between standard electrode potential and electrode potential.
Standard electrode potential is the electrode potential measured under standard conditions (1M concentration, 1 atm pressure, and 25°C temperature), whereas electrode potential is measured under any given conditions.

Explain the Nernst equation and its significance.
The Nernst equation calculates the electrode potential of a cell under non-standard conditions by considering temperature, ion concentration, and standard electrode potential. It helps in determining the feasibility of electrochemical reactions.

What is a concentration cell?
A concentration cell is a type of galvanic cell where both electrodes are the same material, but the electrolyte concentrations are different, generating an electric potential.

Define electrolysis.
Electrolysis is the process in which electrical energy is used to drive a non-spontaneous chemical reaction by passing an electric current through an electrolyte.

What are Faraday’s laws of electrolysis?
Faraday’s first law states that the amount of substance deposited during electrolysis is directly proportional to the charge passed.
Faraday’s second law states that when the same charge is passed through different electrolytes, the mass of substances deposited is proportional to their equivalent weights.

What is the electrochemical series?
The electrochemical series is an arrangement of elements in order of their standard electrode potentials, helping in predicting the feasibility of redox reactions and determining oxidizing and reducing strengths.

Why do metals like zinc and magnesium corrode easily?
Metals like zinc and magnesium have lower electrode potentials, making them more reactive and prone to oxidation, leading to corrosion in the presence of moisture and oxygen.

What is the role of a cathode in an electrochemical cell?
The cathode is the electrode where reduction takes place, meaning it gains electrons during the redox reaction in an electrochemical cell.

How can electrochemical cells be used in daily life?
Electrochemical cells are used in batteries, fuel cells, and electroplating, powering various electronic devices, automobiles, and industrial applications.

What is the difference between an electrolytic cell and a galvanic cell?
A galvanic cell generates electricity from spontaneous reactions, while an electrolytic cell uses electrical energy to drive a non-spontaneous reaction.

How does a fuel cell work?
A fuel cell converts chemical energy from fuel (like hydrogen) into electrical energy through electrochemical reactions, producing electricity with water as a byproduct.

What is the significance of EMF (Electromotive Force) in electrochemistry?
EMF determines the voltage produced by an electrochemical cell, indicating its ability to drive an electric current.

How does the oxidation state of a metal affect its electrode potential?
Higher oxidation states generally result in higher electrode potentials, making the metal more likely to gain electrons and undergo reduction.

How does pH affect electrode potential?
Changes in pH alter ion concentration, influencing the electrode potential as per the Nernst equation.

What happens when a copper rod is placed in zinc sulfate solution?
No reaction occurs because copper has a higher reduction potential than zinc and cannot displace zinc from its sulfate solution.

How does electroplating work?
Electroplating uses electrolysis to coat a metal surface with a thin layer of another metal, enhancing its appearance and preventing corrosion.

What is the role of an inert electrode in electrochemical cells?
An inert electrode, such as platinum or graphite, provides a surface for electron transfer without participating in the reaction itself.

How can corrosion be prevented using electrochemical methods?
Methods like cathodic protection, galvanization, and sacrificial anodes prevent corrosion by altering the electrochemical conditions of metals.

What is the working principle of a lead-acid battery?
A lead-acid battery operates through reversible redox reactions between lead dioxide and lead in sulfuric acid, storing and supplying electrical energy.

What happens to the EMF of a galvanic cell when the temperature increases?
Increasing temperature affects ion mobility and reaction rates, often altering the EMF based on the Nernst equation.

Mastering Electrochemistry – NCERT Solutions for Class 12 Chemistry Chapter 2

Electrochemistry plays a vital role in understanding the interaction between electrical energy and chemical reactions. This topic is essential for students preparing for board exams and competitive entrance tests like JEE and NEET. Chapter 2 of Class 12 Chemistry focuses on the principles of electrochemical cells, redox reactions, conductance, and applications of electrochemistry in daily life.

Understanding Electrochemical Cells

An electrochemical cell is a system where chemical reactions generate electricity or where electrical energy drives chemical changes. There are two main types:

Galvanic (Voltaic) Cells – These cells convert chemical energy into electrical energy through spontaneous redox reactions. The Daniell cell, consisting of zinc and copper electrodes, is a classic example.
Electrolytic Cells – Unlike galvanic cells, these require an external electrical source to drive a non-spontaneous reaction, as seen in electrolysis.

The working principle of these cells is based on oxidation-reduction reactions, where electrons transfer between substances, creating an electric current.

Electrode Potential and the Nernst Equation

Each metal in an electrochemical cell has a tendency to lose or gain electrons, measured as its electrode potential. The standard electrode potential (E°) is recorded under standard conditions (1M concentration, 25°C, and 1 atm pressure).

The Nernst equation helps calculate cell potential under different conditions:

$E^\circ - \frac{0.0591}{n} \log Q$

where E is the cell potential, E° is the standard potential, n is the number of electrons exchanged, and Q is the reaction quotient.

This equation plays a crucial role in predicting how concentration, pressure, and temperature affect an electrochemical reaction’s feasibility.

Electrolysis and Faraday’s Laws

Electrolysis is widely used in industrial applications like electroplating, metal refining, and water splitting. Faraday’s laws of electrolysis define the relationship between the amount of substance deposited during electrolysis and the charge passed:

First Law – The mass of a substance deposited is directly proportional to the charge passed.
Second Law – When the same charge is passed through different electrolytes, the mass deposited is proportional to the equivalent weight of the substance.

These principles help industries optimize metal purification and electroplating techniques.

Conductance in Electrolytic Solutions

Electrolytes conduct electricity through the movement of ions in solution. Conductance depends on:

Electrolyte concentration – Higher ion concentration increases conductivity.
Temperature – Increased temperature enhances ion mobility.
Nature of solute and solvent – Strong electrolytes (e.g., NaCl) dissociate completely, offering high conductance, while weak electrolytes (e.g., acetic acid) dissociate partially.

Two key terms used in electrochemistry are:

Specific Conductance (κ) – Conductance of a solution per unit length and cross-section.
Molar Conductance (Λm) – Conductance of an electrolyte solution containing one mole of solute.

As dilution increases, molar conductance rises due to greater ion mobility.

The Electrochemical Series and Corrosion

The electrochemical series ranks elements based on their standard electrode potentials. This series predicts metal reactivity, displacement reactions, and feasibility of redox processes.

A major application of electrochemistry is corrosion control. Rusting of iron is a common electrochemical process where iron reacts with oxygen and water to form hydrated iron oxide (rust). Methods to prevent corrosion include:

Galvanization – Coating iron with zinc to prevent oxidation.
Cathodic Protection – Using a more reactive metal as a sacrificial anode to protect iron.
Alloying – Mixing metals to enhance resistance against corrosion.

Applications of Electrochemistry in Daily Life

Electrochemistry has practical applications in various fields:

Batteries and Fuel Cells – Rechargeable lithium-ion batteries, lead-acid batteries, and hydrogen fuel cells rely on electrochemical reactions for energy storage and power generation.
Electroplating – Industries use electroplating to coat metals with a thin protective layer, enhancing durability and appearance.
Water Purification – Electrochemical techniques help remove contaminants and disinfect water supplies.

Best Books for Class 12 Chemistry NCERT Solutions Chapter 2

1. NCERT Chemistry Class 12 – NCERT
Covers the entire syllabus with conceptual clarity and step-by-step problem-solving approaches.

2. Physical Chemistry by P. Bahadur – G.R. Bathla Publications
Best for numerical problems and detailed electrochemistry concepts with practice exercises.

3. Modern Approach to Chemical Calculations by R.C. Mukherjee – Bharti Bhawan
A great book for numerical-based questions, including conceptual and application-based problems.

4. Concise Inorganic Chemistry by J.D. Lee – Oxford University Press
Covers in-depth inorganic chemistry principles with a detailed explanation of redox reactions.

5. Organic Chemistry by Morrison and Boyd – Pearson
Although focused on organic chemistry, it provides good insight into reaction mechanisms that apply to electrochemistry.

6. Understanding Chemistry by C.N.R. Rao – Universities Press
Ideal for advanced understanding and competitive exam preparation.

7. Pradeep’s New Course Chemistry – Pradeep Publications
A widely used book with easy-to-understand language, detailed NCERT solutions, and additional practice questions.

8. Dinesh Chemistry Class 12 – S. Chand Publications
Covers both theory and application-based questions with detailed electrochemistry explanations.

9. ABC of Chemistry for Class 12 – Modern Publications
A student-friendly book covering NCERT solutions, competitive exam questions, and additional practice problems.

10. Arihant Chemistry Handbook – Arihant Publications
Quick reference book for competitive exams, summarizing key concepts with solved examples.

11. Exam Idea Chemistry Class 12 – VK Global Publications
Designed for CBSE board exams with a focus on important topics, including electrochemistry.

12. S. Chand’s Advanced Chemistry – S. Chand Publications
A well-structured book with conceptual clarity and numerical practice questions.

13. Numerical Chemistry by P. Bahadur – G.R. Bathla Publications
Best for solving electrochemistry numerical problems with practical applications.

14. Master Resource Book in Chemistry – Arihant Publications
Provides concept-based learning and MCQs for practice.

15. Comprehensive Chemistry Class 12 – Laxmi Publications
A detailed book covering NCERT solutions, additional exercises, and conceptual explanations.

These books provide extensive coverage of Class 12 Chemistry Chapter 2 (Electrochemistry), offering theory, practice problems, and NCERT solutions to help students excel in board exams and competitive tests.

16. Cengage Chemistry for JEE Advanced – Cengage Learning
A comprehensive book with detailed explanations, solved examples, and high-level numerical problems on electrochemistry.

17. GRB Physical Chemistry for Competitions by OP Tandon – GRB Publications
A detailed book for mastering electrochemistry with conceptual clarity, MCQs, and numerical problems, suitable for both board exams and competitive exams.

18. Problems in Physical Chemistry by Narendra Awasthi – Balaji Publications
Focuses on numerical problem-solving with step-by-step solutions, ideal for JEE and NEET aspirants.

19. A Textbook of Physical Chemistry by K.L. Kapoor – McGraw Hill
Provides a deep conceptual understanding of electrochemistry with a theoretical approach and practical applications.

20. Chemistry Part 1 & 2 by Laxmi Publications – Laxmi Publications
Includes NCERT-based explanations, additional exercises, and detailed electrochemistry solutions.

21. CBSE Chapterwise Chemistry Class 12 by Arihant Experts – Arihant Publications
A book designed for CBSE board exams, covering chapter-wise NCERT solutions and extra practice questions.

22. Organic, Inorganic, and Physical Chemistry by OP Tandon – G.R. Bathla Publications
A comprehensive book covering all branches of chemistry with detailed electrochemistry content.

23. Chemistry for Class 12 by R.K. Gupta – Arihant Publications
Provides a complete guide for CBSE board and competitive exam preparation, including theory and numerical problems.

24. Chemistry Class 12 by Xam Idea – VK Global Publications
Follows the NCERT syllabus with additional concept-based questions and solutions for better understanding.

25. Advanced Problems in Physical Chemistry by Neeraj Kumar – Balaji Publications
A higher-level book for competitive exams, focusing on complex electrochemistry problems with detailed explanations.

26. Chemistry Simplified by Disha Experts – Disha Publications
A well-structured book that explains electrochemistry and other chemistry topics with solved NCERT questions.

27. Self-Study Guide Chemistry Class 12 by Pradeep – Pradeep Publications
Covers board exam-oriented questions, NCERT solutions, and in-depth explanations of electrochemistry concepts.

28. CBSE Board Champion Chemistry Class 12 by Educart – Educart Publications
An exam-oriented book providing NCERT-based solutions, past-year questions, and electrochemistry numerical problems.

29. Essential Physical Chemistry by Ranjeet Shahi – Laxmi Publications
A highly recommended book for deep conceptual understanding and numerical practice of electrochemistry.

30. Foundation Course Chemistry Class 12 by MTG Learning Media – MTG Publications
Designed for concept clarity and competitive exams, this book includes NCERT-based electrochemistry solutions and application-based questions.

These books are excellent resources for mastering Class 12 Chemistry Chapter 2 (Electrochemistry), covering both theory and problem-solving to help students succeed in board exams and entrance tests like JEE and NEET.

A clear understanding of NCERT solutions for Class 12 Chemistry Chapter 2 ensures strong conceptual knowledge, making electrochemistry an exciting and applicable subject for future studies and career paths