Class 12 Chemistry - Electrochemistry

1. Electrochemical Cells

• Galvanic/Voltaic Cell: Converts chemical energy to electrical energy (e.g., Daniell Cell).
• Anode: Oxidation (Negative pole) - LOAN (Left Oxidation Anode Negative).
• Cathode: Reduction (Positive pole).

2. Nernst Equation

For the reaction: $aA + bB \rightarrow cC + dD$ $$E_{\text{cell}} = E^\circ_{\text{cell}} - \frac{0.059}{n} \log \frac{[C]^c [D]^d}{[A]^a [B]^b}$$ At equilibrium, $E_{\text{cell}} = 0$. So, $E^\circ_{\text{cell}} = \frac{0.059}{n} \log K_c$

3. Kohlrausch's Law

The limiting molar conductivity of an electrolyte is the sum of the limiting ionic conductivities of the cation and the anion. $\Lambda^\circ_m = \nu_+ \lambda^\circ_+ + \nu_- \lambda^\circ_-$

4. Batteries

• Primary: Non-rechargeable (Dry cell, Mercury cell).
• Secondary: Rechargeable (Lead storage battery).
• Fuel Cells: $H_2\text{-}O_2$ cell used in Apollo space program. Pollution free.

5. Corrosion

Rusting of iron is an electrochemical phenomenon. Prevention: Barrier protection, Galvanization (Zinc coating), Cathodic protection.

Solve numericals on Nernst Equation—it's a sure-shot 3 marker! 🧪🔋