Which of the following compounds contains an organic functional group?

• A. ${\mathrm{NaCl}}_{\mathrm{}}$ (sodium chloride)
• B. $H_{2}O$ (water)
• C. ${\mathrm{CH}}_3\mathrm{OH}$ (methanol)
• D. ${\mathrm{Na}}_2\mathrm{SO}{4}_2$ (sodium sulfate)

Answer: (C)

Verified step by step guidance

1. Understand what an organic functional group is: it is a specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules, typically containing carbon atoms bonded to other elements like oxygen, nitrogen, or halogens.
2. Examine each compound to identify the presence of carbon atoms, since organic functional groups are part of organic compounds which always contain carbon.
3. Check sodium chloride (NaCl): it contains sodium and chlorine, no carbon atoms, so it does not have an organic functional group.
4. Check water (H\_2O): it contains hydrogen and oxygen, no carbon atoms, so it does not have an organic functional group.
5. Check methanol (CH\_3OH): it contains carbon bonded to hydrogen and a hydroxyl group (-OH), which is a classic organic functional group called an alcohol group, so this compound contains an organic functional group.