If the iodate ion has the formula IO3-, what is the name for the acid with the formula HIO4
The Correct Answer and Explanation is:
Correct Answer: Periodic acid
Explanation:
To determine the name of the acid HIO₄, first understand its relationship with the iodate family of oxyanions. The ion given is IO₃⁻, which is known as iodate. Oxyacids are named based on the polyatomic ion they contain.
In the halogen oxyacid series (like chlorine, bromine, and iodine), the names of the acids change based on the number of oxygen atoms:
- Hypoiodous acid – HIO (contains IO⁻)
- Iodous acid – HIO₂ (contains IO₂⁻)
- Iodic acid – HIO₃ (contains IO₃⁻)
- Periodic acid – HIO₄ (contains IO₄⁻)
Since HIO₄ contains the periodate ion (IO₄⁻), it is called periodic acid. The name follows the convention of using the prefix per- and the suffix -ic to indicate the highest oxygen content in the series of acids for that element.
The naming system works as follows:
- If the anion ends in -ate, the acid ends in -ic.
- If it ends in -ite, the acid ends in -ous.
- If per- is added to an -ate ion, it means one more oxygen than the base form.
- If hypo- is added to an -ite ion, it means one fewer oxygen than the base form.
Therefore, since IO₃⁻ is iodate, and IO₄⁻ is periodate, the corresponding acid HIO₄ is called periodic acid. It is the most oxidized form of the iodine oxyacids and is commonly used in analytical chemistry and organic oxidation reactions.
