Which aqueous acid is formed when the bromide ion (Br^-) reacts with hydrogen ions?

• A. Bromous acid (HBrO_2)
• B. Bromic acid (HBrO_3)
• C. Hypobromous acid (HBrO)
• D. Hydrobromic acid (HBr)

Answer: (D)

Verified step by step guidance

1. Identify the species involved: the bromide ion (Br⁻) and hydrogen ions (H⁺) in aqueous solution.
2. Understand that when a halide ion (like Br⁻) reacts with hydrogen ions, it typically forms the corresponding binary hydrogen halide acid, not an oxyacid.
3. Recall the difference between binary acids and oxyacids: binary acids consist of hydrogen and a halogen (e.g., HBr), while oxyacids contain hydrogen, oxygen, and the halogen (e.g., HBrO, HBrO₂, HBrO₃).
4. Since Br⁻ is just the bromide ion without oxygen, combining it with H⁺ forms hydrobromic acid (HBr), which is a binary acid.
5. Therefore, the acid formed is hydrobromic acid (HBr), not any of the bromous, bromic, or hypobromous acids, which are oxyacids containing oxygen.