Chlor-Alkali Process: NaOH, NaCl, and Cl₂

The chlor-alkali process electrolyzes aqueous sodium chloride NaCl (58.44 g/mol) to produce chlorine Cl₂, hydrogen H₂, and sodium hydroxide NaOH (40.00 g/mol). The overall reaction is 2 NaCl + 2 H₂O → Cl₂ + H₂ + 2 NaOH. Every mole of NaCl consumed yields one mole of NaOH — so converting a plant's daily NaOH output to required brine mass starts with molar mass and coefficients.

Chlorine Cl₂ (diatomic molar mass 70.90 g/mol) feeds bleach, PVC, and water treatment. Hydrogen H₂ (2.016 g/mol) is captured for fuel or ammonia synthesis. Engineers track current efficiency: not every electron produces the intended product. Percent yield and faraday calculations extend the same mole logic taught with silver nitrate AgNO₃ and sodium chloride NaCl precipitation in lab.

Compare potassium analogs: potassium chloride KCl (74.55 g/mol) and potassium hydroxide KOH (56.11 g/mol) follow identical stoichiometry with different masses. Molar mass differences explain why caustic soda (NaOH) and caustic potash (KOH) require different weighing for the same mole count in solution preparation.