- Saponification: Alkaline hydrolysis of an ester where the ester is boiled with sodium hydroxide, NaOH or potassium hydroxide, KOH solution to produce an alcohol and a sodium or potassium salt of a carboxylic acid.
- Soap is not an effective cleansing agent in hard water but is only effective in soft water. Detergent is an effective cleansing agent in both hard water and soft water.
- Soft water: Water that does not contain mineral salts such as magnesium salt or calcium salts.
- Hard water: Water that contain mineral salts.
- Food additives are substances added to food to preserve flavor or enhance its taste and appearance. Types of additives are preservatives, antioxidants, flavourings, stabilizers, thickening agents and food dyes (colourings).
- Medicines: a compound or preparation used for the treatment or prevention of disease, especially a drug or drugs taken by mouth. Types of modern medicines are analgesics, antibiotics, stimulants, antidepressant and antipsychotic.