Question

which of the following is an organic compound?
○ ammonia (nh₃)
○ calcium sulfide (cas)
○ octane (c₈h₁₈)
○ sulfur trioxide (so₃)

Explanation:

Organic compounds are generally defined as compounds containing carbon - hydrogen (C - H) bonds, and most also contain carbon atoms (with some exceptions like carbonates, cyanides, etc.).

• Ammonia ($NH_3$) has no carbon atoms, so it is not an organic compound.
• Calcium sulfide (CaS) is an ionic compound composed of calcium and sulfide ions, with no carbon atoms, so it is not organic.
• Octane ($C_8H_{18}$) contains carbon and hydrogen atoms and has C - H bonds, so it is an organic compound (it is a hydrocarbon, specifically an alkane).
• Sulfur trioxide ($SO_3$) has no carbon atoms, so it is not an organic compound.

Answer:

C. octane ($C_8H_{18}$)