# Electrochemistry Notes, Class 12 Chemistry | SwaVid Electrochemistry, NCERT Class 12 Chemistry: notes with key ideas, formulas, common mistakes and 3 quick checks with worked answers. Canonical: https://www.swavid.com/cbse/class-12/chemistry/chapter/electrochemistry Source: https://www.swavid.com/cbse/class-12/chemistry/chapter/electrochemistry # Electrochemistry ## Formulas and definitions ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 12 Chemistry on SwaVid ### Galvanic and electrolytic cells ### Nernst equation and cell potential ### Conductance and molar conductivity ### Kohlrausch's law of independent migration ### Electrolysis and Faraday's laws ### Batteries, fuel cells, and corrosion ### Next chapter ### Related chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 12 › Chemistry › Electrochemistry Notes written by SwaVid from the NCERT textbook. Class 12 Chemistry, Unit 2. Key ideas, formulas and common mistakes. CBSE prints 9 marks for Unit 2, not for this chapter alone. Short answer. This chapter explains the interconversion of chemical energy and electrical energy in electrochemical and electrolytic cells. Students learn to calculate cell potentials using the Nernst equation, evaluate electrolytic conductance, and apply Faraday's laws of electrolysis. Source: NCERT Chemistry Part I (Reprint 2026-27) , Unit 2, Electrochemistry A galvanic cell converts chemical energy from a spontaneous redox reaction into electrical energy, whereas an electrolytic cell uses external electrical energy to carry out a non-spontaneous chemical reaction. The standard hydrogen electrode serves as the reference with an assigned potential of 0.00 V. The Nernst equation relates cell potential to reaction quotient and ion concentrations at non-standard conditions. At equilibrium, the cell potential becomes zero, allowing the calculation of equilibrium constants and standard Gibbs energy changes. Electrolytic solutions conduct electricity through ion migration. Conductivity decreases with dilution because the number of current-carrying ions per unit volume decreases, whereas molar conductivity increases with dilution. At infinite dilution, each ion makes a definite individual contribution to the total molar conductivity of an electrolyte, independent of the co-ion. This law helps calculate the limiting molar conductivity of weak electrolytes and their degree of dissociation. Faraday's first law states that the mass of substance deposited is proportional to the electric charge passed. The second law states that when the same quantity of electricity passes through different electrolytes, the masses deposited are proportional to their chemical equivalent weights. Commercial galvanic cells include primary batteries, rechargeable secondary batteries like the lead storage cell, and fuel cells that convert combustion energy directly into electrical energy. Corrosion is an electrochemical process where a metal is oxidised by atmospheric oxygen in the presence of moisture. Try each question first. Then tap it to see the answer. Cathode is Ag⁺/Ag and anode is Mg²⁺/Mg. E°cell = E°cathode - E°anode E°cell = 0.80 V - (-2.37 V) = 3.17 V 3.17 V Charge Q = I × t = 1.5 A × (10 × 60 s) = 900 C Cu²⁺ + 2e⁻ → Cu, so n = 2 mol of electrons per mol of Cu m = (M × Q) / (n × F) = (63.5 × 900) / (2 × 96500) = 57150 / 193000 ≈ 0.296 g 0.296 g Λm = (1000 × κ) / c Λm = (1000 × 0.0014) / 0.01 = 1.4 / 0.01 = 140 S cm² mol⁻¹ 140 S cm² mol⁻¹ Chemical Kinetics . Solutions . The d- and f-Block Elements . The 10 chapters of Class 12 Chemistry . CBSE does not give marks to one chapter. It prints 9 marks for Unit 2, Electrochemistry, which includes Electrochemistry. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. Chemical Kinetics. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Unit 2 NCERT book - 9 marks, Unit 2 - 3 quick checks - Using oxidation potential instead of reduction potential in E°cell calculations . Always use IUPAC standard reduction potentials for both electrodes, following the formula E°cell = E°cathode - E°anode. - Confusing the dilution trends of conductivity and molar conductivity . Remember that conductivity (κ) decreases on dilution due to fewer ions per unit volume, while molar conductivity (Λm) increases on dilution. - Mismatched units in molar conductivity calculation . When using Λm = (1000 × κ) / c, ensure κ is in S cm⁻¹ and c is in mol L⁻¹. If κ is in S m⁻¹, divide by 1000 × c (mol m⁻³). - Incorrect value of n in the Nernst equation . Write the fully balanced overall redox equation first, then count the total moles of electrons exchanged between the oxidising and reducing agents. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 12](https://www.swavid.com/cbse/class-12) - [Chemistry](https://www.swavid.com/cbse/class-12/chemistry/chapters) - [Start free →](https://www.swavid.com/signup) - [All 10 chapters](https://www.swavid.com/cbse/class-12/chemistry/chapters) - [NCERT Chemistry Part I (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-12/chemistry/chapter/chemical-kinetics) - [Open notes](https://www.swavid.com/cbse/class-12/chemistry/chapter/solutions) - [Open notes](https://www.swavid.com/cbse/class-12/chemistry/chapter/the-d-and-f-block-elements) - [Class 12 Chemistry](https://www.swavid.com/cbse/class-12/chemistry/chapters) - [Start free →](https://www.swavid.com/signup)