handedness. In fact, one of the easiest visualizations of chirality is to think of your own hands, as
shown in Figure 2.9. Although essentially identical, your left hand will not be able to fit into a right-
handed glove. Achiral objects have mirror images that can be superimposed; for example, a fork is
identical to its mirror image and is therefore achiral.
Figure 2.9. Hands as Examples of Chiral Structures
Each hand has a nonsuperimposable mirror image.KEY CONCEPT
Chirality = handednessOn the MCAT, we will often see this concept tested when there is a carbon atom with four different
substituents. This carbon will be an asymmetrical core of optical activity and is known as a chiral
center. As mentioned earlier, chiral centers lack a plane of symmetry. For example, the C-1 carbon
atom in 1-bromo-1-chloroethane has four different substituents. As shown in Figure 2.10, this
molecule is chiral because it is not superimposable on its mirror image.