1. Nothing is more memorable than a smell. One scent can be unexpected, momentary and fleeting, yet conjure up a childhood summer beside a lake in the mountains. Diane Ackerman Nothing is more memorable than a smell. One scent can be unexpected, momentary and fleeting, yet conjure up a childhood summer beside a lake in the mountains. Diane Ackerman What's in a name? That which we call a rose by any other name would smell as sweet. William Shakespeare What's in a name? That which we call a rose by any other name would smell as sweet. William Shakespeare The reference is often used to imply that the names of things do not affect what they really are.

2. Overview In this section, learn about the chemistry of soap- making, find about how soaps and detergents clean, and study the chemistry of emulsions and emulsifiers.

3. After completing this lesson you should be able to : Describe the production of soaps by the alkaline hydrolysis of fats and oils to form water-soluble ionic salts called soaps. Know that soap ions have a long covalent tail, readily soluble in covalent compounds (hydrophobic), and an ionic carboxylate head which is negatively charged and water soluble (hydrophilic). Apply your understanding of alkaline hydrolysis and prepare a scented bar of soap.

4. Soaps Soaps are salts of fatty acids. Alkaline hydrolysis is used to make sodium salts of fatty acids Soaps are formed by the alkaline hydrolysis of fats and oils by sodium or potassium hydroxide by boiling under reflux conditions:. Glyceryl tristearate + 3NaOH + 3Na + Glycerol Sodium stearate (soap) COPY

5. This animation describes the formation of soap by the alkaline hydrolysis of fats/oils followed by neutralisation to form sodium salts of fatty acids. Click here Formation of soap

6. The structure of soap The long covalent hydrocarbon chain gives rise to the hydrophobic (water hating) and oil-soluble (non-polar) properties of the soap molecule (represented in yellow). The charged carboxylate group (represented in blue) is attracted to water molecules (hydrophilic). In this way, soaps are composed of a hydrophilic head and a hydrophobic tail: COO - Na + Hydrophobic tail Hydrophilic head COPY