Problem 63 - Chemistry The Molecular Nature of Matter

Question

Name these acids that bromine forms. (a) \(\mathrm{HBrO}_{4}\), (b) \(\mathrm{HBrO}_{3}\), (c) \(\mathrm{HBrO}_{2},\) (d) \(\mathrm{HBrO}\) (e) \(\mathrm{HBr}\)

Step-by-Step Solution

Answer

(a) Perbromic acid, (b) Bromic acid, (c) Bromous acid, (d) Hypobromous acid, (e) Hydrobromic acid.

Step 1: Assigning Nomenclature for Oxoacids

When naming oxoacids, if the acid has the highest number of oxygen atoms, it is given the prefix 'per-' and the suffix '-ic.' If it has one less oxygen than the highest, it is simply given the suffix '-ic.' One less than that gets the prefix 'hypo-' and the suffix '-ous.' One less oxygen than '-ous' gets the prefix 'hypo-' and the suffix '-ic.'

Step 2: Naming Each Acid

(a) For \(\mathrm{HBrO}_{4}\), since it has the highest number of oxygens for bromine oxoacids, it is named perbromic acid. (b) For \(\mathrm{HBrO}_{3}\), it is one less than the highest, so it is bromic acid. (c) For \(\mathrm{HBrO}_{2}\), it is one less than bromic, so it is bromous acid. (d) For \(\mathrm{HBrO}\), it is one less than bromous, so it is hypobromous acid.

Step 3: Naming Hydrogen Halides

(e) For \(\mathrm{HBr}\), since it does not contain oxygen, it is not an oxoacid but a binary acid. The binary acid naming convention instructs to use the prefix 'hydro-' and the suffix '-ic' followed by the word 'acid', which results in hydrobromic acid.

Key Concepts

Oxoacid Nomenclature

Understanding the naming of oxoacids is pivotal for students who are navigating through the intricate details of chemistry. These acids are characterized by the presence of oxygen in their molecular structure alongside hydrogen and another element, typically a nonmetal. When assigning names to oxoacids, there's a particular pattern that hinges on the number of oxygen atoms present.

For an acid with the maximum number of oxygens, you'd use the prefix 'per-' and the suffix '-ic.' Imagine an acid wearing a cape, standing atop a mountain—it's the 'per-'fect acid with the most oxygen atoms in its category. Going down the 'mountain' of oxygen atoms, if there's one less, the acid maintains just the '-ic' suffix. With another oxygen less, we adorn the name with the prefix 'hypo-' and change the suffix to '-ous.' And if it's missing yet more oxygen, it retains the 'hypo-' but switches back to '-ic.' This systematic approach helps to keep the nomenclature clear and structured, simplifying the learning process for students.

Bromine Oxoacids

Diving into the world of bromine oxoacids, we encounter a series of compounds where bromine is paired with oxygen in varying amounts. Each has its distinct name conforming to the principles of oxoacid nomenclature.

Take, for instance, \(\mathrm{HBrO}_{4}\), which stands proudly as perbromic acid due to its 'peak' oxygen content. A step down to \(\mathrm{HBrO}_{3}\) lands us with bromic acid. Falling further to \(\mathrm{HBrO}_{2}\), we enter the territory of bromous acid. Lastly, a single oxygen atom in \(\mathrm{HBrO}\) awards it the title of hypobromous acid. These systematic names allow students not only to identify the compound easily but also to infer the relative number of oxygen atoms without peering into the molecular structure.

Binary Acid Naming Convention

Stepping away from the oxygen-rich realm of oxoacids, we come across the simple yet significant binary acids. These compounds prefer a minimalistic lifestyle with just hydrogen and one other nonmetal element—no oxygen in sight.

The convention here is equally systematic: prefix the element with 'hydro-', add the '-ic' suffix, and end with 'acid.' For example, \(\mathrm{HBr}\) becomes hydrobromic acid. This 'hydro-' prefix is like a flag signaling that we're dealing with a duo—a binary compound. It's a straightforward naming process that offers a helping hand to students, providing a clear distinction between binary acids and their oxoacid cousins.