Achiral means?

Achiral means?

• A. A molecule that is not superimposable on its mirror image
• B. A molecule with no stereocenters
• C. A molecule that is superimposable on its mirror image
• D. A molecule with internal symmetry that is non-chiral

Answer: (C)

Achiral means a molecule is superimposable on its mirror image. If you place the molecule beside its reflection and you can rotate or translate it so both structures line up exactly, there is a symmetry element (like a mirror plane, a center of symmetry, or an improper rotation) that makes the two identical. That handedness is absent, which is why the molecule is achiral. This is the opposite of chirality, where the molecule and its mirror image are non-superimposable. It’s also worth noting that having stereocenters doesn’t always make a molecule chiral; some molecules with stereocenters are achiral because they possess internal symmetry (meso compounds).

Achiral means a molecule is superimposable on its mirror image. If you place the molecule beside its reflection and you can rotate or translate it so both structures line up exactly, there is a symmetry element (like a mirror plane, a center of symmetry, or an improper rotation) that makes the two identical. That handedness is absent, which is why the molecule is achiral. This is the opposite of chirality, where the molecule and its mirror image are non-superimposable. It’s also worth noting that having stereocenters doesn’t always make a molecule chiral; some molecules with stereocenters are achiral because they possess internal symmetry (meso compounds).