What is the name of the acid whose formula is HI? Spell out the full name of the acid.

• A. Iodous acid
• B. Hydroiodic acid
• C. Iodic acid
• D. Hydroiodous acid

Answer: (B)

Verified step by step guidance

1. Identify the elements present in the acid formula. Here, the formula is HI, which consists of hydrogen (H) and iodine (I).
2. Recognize that acids starting with 'H' and containing a halogen (like iodine) are typically named as 'hydro' + halogen root + 'ic acid'.
3. Recall that when the acid contains only hydrogen and one halogen element without oxygen, the naming convention uses the prefix 'hydro-' and the suffix '-ic acid'.
4. Apply this rule to HI: the halogen is iodine, so the acid name becomes 'hydroiodic acid'.
5. Confirm that other options like 'iodous acid' or 'iodic acid' refer to oxyacids of iodine, which contain oxygen atoms, so they do not apply to HI.