Butane is chlorinated with $\mathrm{Cl}{}_2$ and light and the product 2-chlorobutane is isolated. It is obtained as

Abstraction of a secondary H gives a planar (sp2) 2-butyl radical. $\mathrm{Cl}{}_2$ attacks either face with equal probability, giving equal amounts of the $(R)$ and $(S)$ enantiomers, a racemic mixture with no optical activity. 2-Chlorobutane has one stereocentre, so a meso form cannot exist.