Without a chiral influence (for example a chiral catalyst, solvent or starting material), a chemical reaction that makes a chiral product will always yield a racemate. That can make the synthesis of a racemate cheaper and easier than making the pure enantiomer, because it does not require special conditions. This fact also leads to the question of how biological homochirality evolved on what is presumed to be a racemic primordial earth.
The reagents of, and the reactions that produce, racemic mixtures are said to be "not stereospecific" or "not stereoselective", for their indecision in a particular stereoisomerism. A frequent scenario is that of a planar species (such as an sp carbon atom or a carbocation intermediate) acting as an electrophile. The nucleophile will have a 50% probability of hitting either of the two sides of the planar grouping, thus producing a racemic mixture: