Which of the following contains a functional group characteristic of organic compounds?

• A. ${\mathrm{CH}}_3\mathrm{OH}$ (methanol)
• B. ${\mathrm{Ca}}_{\mathrm{CO}}{3}_2$ (calcium carbonate)
• C. ${\mathrm{Na}}_2\mathrm{SO}{4}_2$ (sodium sulfate)
• D. ${\mathrm{Na}}_{\mathrm{Cl}}$ (sodium chloride)

Answer: (A)

Verified step by step guidance

1. Identify what a functional group is: a specific group of atoms within molecules that is responsible for the characteristic chemical reactions of those molecules.
2. Examine each compound to determine if it contains a functional group typical of organic chemistry, which usually involves carbon atoms bonded to other elements like oxygen, nitrogen, or halogens.
3. Look at methanol (CH\_3OH): it contains a hydroxyl group (-OH) attached to a carbon atom, which is a classic functional group in organic compounds known as an alcohol group.
4. Check calcium carbonate (CaCO\_3), sodium sulfate (Na\_2SO\_4), and sodium chloride (NaCl): these are inorganic salts and do not contain carbon-based functional groups characteristic of organic molecules.
5. Conclude that methanol contains the functional group characteristic of organic compounds because it has a carbon atom bonded to a hydroxyl group, making it an organic molecule with an alcohol functional group.