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Beyond the textbook: concentration cells, cells with a precipitate or a complex, finding a solubility product or a pH from an emf, and electrolysis with competing ions. The problems that JEE, NEET and A-Level Chemistry ask most, with a full timed paper.

What's inside

1. Concentration cells and emf from solubility: Two beakers can hold the same metal and the same ion and still make a cell, if one solution is stronger than the other. The emf then comes from the difference in concentration alone. This lesson shows how to read such a cell, and how a very small solubility can be found from a voltage.
2. Cells that measure pH and equilibrium: A pH meter shows a number, but inside it measures a voltage. A hydrogen electrode, a glass bulb or a silver wire can each turn a concentration into an emf. This lesson shows how the emf of a cell gives a pH, a solubility product and the formation constant of a complex ion.
3. Electrolysis with competing ions: A plating bath or a refinery liquor seldom holds only one ion. When several ions can take electrons at the cathode, or give them up at the anode, the potential and the concentration decide who goes first. This lesson shows how to predict the order, how clean a separation can be, and what happens when hydrogen joins the competition.