Question

For each compound, determine whether the molecule has an internal mirror plane of symmetry. If it does, draw the mirror plane on a three-dimensional drawing of the molecule. If the molecule does not have an internal mirror plane, determine whether the structure is chiral.

a) Identify and draw the mirror plane for a molecule with an internal mirror plane.

b) Determine the chirality of a molecule without an internal mirror plane.

Answer 1

To determine if a molecule has an internal mirror plane, draw its three-dimensional structure using VSEPR theory. If no mirror plane exists, the molecule may be chiral, meaning it has enantiomers that are non-superimposable mirror images, and it exhibits optical activity.

Step-by-step explanation:

To determine whether a molecule has an internal mirror plane of symmetry, you should first do the following:

1. Draw the Lewis structure.
2. Figure out the molecular geometry (using VSEPR theory).
3. Visualize or draw the molecule in three-dimensional space to locate any potential planes of symmetry.

If a molecule has a mirror plane, you would draw it in such a way that one half of the molecule is reflected symmetrically across the plane to the other half. However, if the molecule lacks a mirror plane, it may be chiral. A chiral molecule is one that cannot be superimposed on its mirror image, meaning it lacks symmetry. For example, a compound with a central carbon atom that is bonded to four different substituents is chiral. Since such a molecule has no planes of symmetry, it exists as two enantiomers that are non-superimposable mirror images of each other.

Optical activity is a property exhibited by chiral compounds, which enables them to rotate the plane of plane-polarized light. This characteristic is measured using a polarimeter.