To determine which of the given formulas represents a hydrocarbon, let's first understand what hydrocarbons are. Hydrocarbons are compounds that consist only of carbon (C) and hydrogen (H) atoms.
We will evaluate each given formula to see if it only includes hydrogen and carbon atoms:
1. HCOOH:
- Contains: Hydrogen (H), Carbon (C), and Oxygen (O).
- Since it includes oxygen (O), this is not a hydrocarbon.
2. CH₂O:
- Contains: Hydrogen (H), Carbon (C), and Oxygen (O).
- Since it includes oxygen (O), this is not a hydrocarbon.
3. CH₃OH:
- Contains: Hydrogen (H), Carbon (C), and Oxygen (O).
- Since it includes oxygen (O), this is not a hydrocarbon.
4. CH₄:
- Contains: Only Hydrogen (H) and Carbon (C).
- This fulfills the criteria for a hydrocarbon.
Therefore, the formula CH₄ (methane) is a hydrocarbon because it consists exclusively of hydrogen and carbon atoms.
