Fat saponification and how soap micelles clean

ChemistryBiomolecules & PolymersAges 17–18

Saponification mode: a fat molecule (a glycerol backbone plus three fatty-acid residues) is cut by OH⁻ ions at its three ester bonds, splitting into three soap salt molecules and one glycerol molecule; the rate rises clearly with temperature, alongside the equation and the mass of soap obtained from 1 mol of fat. Washing mode: an oil drop clings to fabric, and soap molecules turn their hydrophobic tails into the oil and their hydrophilic heads outward, forming a micelle that pulls the oil drop off the fabric.