Bio-diesel is a clean burning alternative fuel, produced from domestic, renewable resources. Bio-diesel can be blended at any level with petroleum diesel to create a bio-diesel blend. It can be used in compression-ignition (diesel) engines with little or no modification. Bio-diesel is simple to use, biodegradable, non-toxic, and essentially free of sulphur and aromatics. This paper presents the two following identifiable topic areas as key themes: 1. preparation of an aqueous solution of sodium hydroxide – as a catalyst, which can be activated by the most MeO- active groups, and can therefore be converted to methyl esters (biodiesel) from triglyceride. Methoxide (MeO-) was produced from sodium hydroxide (NaOH) and methanol (MeOH) in a batch reactor: NaOH + MeOH = H2O + Na+ + MeO-. During bio-diesel production, methoxide is incorrectly referred to as the product of mixing methanol and sodium hydroxide. An aqueous solution of sodium hydroxide – was prepared as a catalyst, by using different amounts of water at the same temperature. The reaction with lower water took place at the highest and quickest degrees of NaOH conversion and thus more MeO- active groups. The water was effective as an inhibitor.