Which of the following formulas represents an organic compound?

• A. ${\mathrm{NaCl}}_{\mathrm{}}$
• B. $H_2\mathrm{SO}{4}_{\mathrm{}}$
• C. ${\mathrm{CH}}_4$
• D. ${\mathrm{CaCO}}_3$

Answer: (C)

Verified step by step guidance

1. Understand the definition of an organic compound: Organic compounds primarily contain carbon atoms bonded to hydrogen, and often other elements like oxygen, nitrogen, sulfur, etc. The key feature is the presence of carbon-hydrogen (C-H) bonds.
2. Examine each given formula to identify if it contains carbon and hydrogen atoms bonded together:
3. 1. NaCl (sodium chloride) is an ionic compound made of sodium and chlorine ions, with no carbon atoms.
4. 2. H2SO4 (sulfuric acid) contains hydrogen, sulfur, and oxygen, but no carbon atoms, so it is inorganic.
5. 3. CH4 (methane) contains one carbon atom bonded to four hydrogen atoms, fitting the definition of an organic compound.
6. 4. CaCO3 (calcium carbonate) contains calcium, carbon, and oxygen, but the carbon is part of a carbonate ion (CO3^2-), which is inorganic.