To determine which chemical formula represents the hydroxide ion, let's examine each option step-by-step:
1. OH⁻
- This formula consists of one oxygen (O) atom and one hydrogen (H) atom, and it has a negative charge (⁻). This aligns with the chemical composition and charge of the hydroxide ion.
2. H⁺
- This formula consists of a single hydrogen (H) atom with a positive charge (⁺). It is known as a proton or hydrogen ion, not hydroxide.
3. H₃O⁺
- This formula represents the hydronium ion, which consists of three hydrogen atoms (H) and one oxygen atom (O) with an overall positive charge (⁺). This is not the hydroxide ion.
4. H₂O
- This formula represents water, which consists of two hydrogen atoms (H) and one oxygen atom (O). This molecule is neutral and not the hydroxide ion.
Based on this analysis, OH⁻ is the chemical formula that represents the hydroxide ion.
Therefore, the correct answer is:
[tex]\[ \text{OH}^{-} \][/tex]
