Which of the following statements best describes chirality in organic molecules?

• A. Chirality is a property of molecules that contain only $C$ and $H$ atoms.
• B. Chirality is the ability of a molecule to rotate plane-polarized light.
• C. Chirality refers to the presence of a $\mathrm{double} \mathrm{bond}$ in a molecule.
• D. Chirality occurs when a molecule has a non-superimposable mirror image.

Answer: (D)

Verified step by step guidance

1. Understand the concept of chirality: Chirality in organic chemistry refers to a property of a molecule that makes it non-superimposable on its mirror image, much like how left and right hands are mirror images but not identical.
2. Identify the structural feature responsible for chirality: Typically, chirality arises in molecules that have a carbon atom bonded to four different substituents, known as a chiral center or stereocenter.
3. Evaluate the given statements: Analyze each statement to determine if it accurately describes chirality. For example, chirality is not limited to molecules with only carbon and hydrogen, nor is it directly related to the presence of a double bond.
4. Consider the ability to rotate plane-polarized light: While chiral molecules can rotate plane-polarized light, this is a consequence of chirality, not the definition itself.
5. Select the correct statement: The statement that best describes chirality is that it occurs when a molecule has a non-superimposable mirror image, as this directly relates to the structural property of chirality.