The chemical name for ClO3- is “chlorate ion”. Therefore, the name of HClO3 is
A. hydrochloric acid.
B. chloroform.
C. hydrogen trioxychloride.
D. chlorous acid.
E. chloric acid.
The correct answer and explanation is :
The correct answer is: E. chloric acid.
Explanation (300 words):
To determine the name of HClO₃, we need to understand the rules of naming oxyacids, which are acids composed of hydrogen, oxygen, and another element (in this case, chlorine).
The polyatomic ion ClO₃⁻ is called the chlorate ion. When hydrogen is added to a polyatomic ion to form an acid, the name of the acid depends on the ending of the polyatomic ion:
- If the ion ends in -ate, the acid name ends in -ic acid.
- If the ion ends in -ite, the acid name ends in -ous acid.
Since ClO₃⁻ is chlorate, and HClO₃ is its corresponding acid (one hydrogen ion added), we follow this rule:
- Replace -ate with -ic acid → chlorate → chloric acid.
Thus, HClO₃ is named chloric acid.
Let’s quickly go over the other options:
- A. Hydrochloric acid – This is the correct name for HCl, which is a binary acid (hydrogen + halogen, no oxygen). It does not apply here.
- B. Chloroform – This is an entirely different compound with the formula CHCl₃ and is not an acid.
- C. Hydrogen trioxychloride – While this is a technically descriptive name, it does not follow the IUPAC naming convention for acids and is not used in common nomenclature.
- D. Chlorous acid – This is the acid form of the chlorite ion (ClO₂⁻), not chlorate.
Therefore, the correct systematic name of HClO₃ based on the chlorate ion is chloric acid, answer E.