Which of the following is the correct chemical formula for the hydronium ion?

• A. OH-
• B. H3O+
• C. NH4+
• D. HCO3-

Answer: (B)

Verified step by step guidance

1. Understand that the hydronium ion is formed when a water molecule (H2O) gains an extra proton (H+).
2. Recall that a proton (H+) is essentially a hydrogen ion without its electron, so when it attaches to water, the formula changes.
3. Combine the water molecule (H2O) with the extra proton (H+) to form the hydronium ion, which has one more hydrogen than water.
4. Write the chemical formula by adding the extra hydrogen to water, resulting in H3O+, indicating a positive charge due to the extra proton.
5. Compare this formula to the options given and identify H3O+ as the correct formula for the hydronium ion.