If you work in the photography industry or have any rubber items in your home, you’ve most likely come in contact with hydrochloric acid, a common type of binary acid. In this lesson, you’ll explore binary acids, including their characteristics and how they differ from binary compounds.
What Are Binary Acids?
What do you think the compounds hydroiodic acid, hydrofluoric acid, and hydrobromic acid, have in common? You may have noticed that each comound contains a hydrogen atom, but did you know that iodine, fluorine, and bromine are nonmetallic elements, which makes these compounds binary acids? Binary acids are acids composed of two atoms, a hydrogen element and a nonmetal element. Hydroiodic acid, hydrofluoric acid, and hydrobromic acid are binary acids because they have a hydrogen element and nonmetal element (iodine, fluorine and bromine) bonded together.
In contrast to metals, which are shiny and ductile, nonmetals are dull and brittle.So, how do you know if you are working with a nonmetal? Well, for one thing, you can find them on the periodic table, like this one:
Characteristics of Binary Acids
In chemistry, acids dissociate, or break apart, into hydrogen ions, which are positively charged, and anions, which are negatively charged, when dissolved in water.
While strong acids, like hydrochloric acid, completely dissociate into ions, less than 10% of weak acids, such as hydrofluoric acid, dissociate into ions. The strength of a binary acid depends upon a number of chemical factors, such as bond strength, dissociation constant (pKa), and electronegativity.Some binary acids are stronger than others. For example, hydrochloric acid is a stronger acid than hydrofluoric acid.
Although strong, HCI has longer, weaker bonds that make it easier for it to dissociate in a solution. While the weaker acid, HF has short bonds that make it more difficult to disassociate. The shorter the bond linking atoms in a molecule together, the greater the bond stability. The greater the bond stability, the less likely a molecule will be to dissociate.
Binary Acids or Binary Compound?
When observing molecules, one way to tell the difference between a binary acid and a binary compound is to consider its physical state.
Aqueous molecules, as denoted by the symbol ‘aq’, are acids. This is because acids are found in water, or aqueous solutions. If the molecule is a gas or liquid, as denoted by the symbols ‘g’ or ‘l,’ it’s a binary compound.
Binary Acid Nomenclature
In chemistry, nomenclature refers to the process of creating a name for a given compound. Naming binary acids and compounds is no different from naming chemical compounds in that each process follows a set of rules. When naming a binary acid, you’ll use ‘hydro’ as the prefix, and ‘ic’ as the suffix.
Do you remember our discussion on nonmetal elements and how to identify one on the periodic table? The root word, where you attach the prefix and suffix, is based upon the name of the nonmetal element.In naming the binary acid, you’ll place ‘hydro’ in front of the nonmetal root word and change it’s ending to ‘ic.’ By comparison, a binary compound, as indicated by ‘g’ or ‘l,’ will end in ‘-ide.’Let’s look at some examples.
Example 1: HFHF = hydrogen fluoride or HF = hydro – fluor – ic acid = hydrofluoric acidExample 2: HBrHBr = hydrogen bromide or HBr = hydro – brom – ic acid = hydrobromic acidIn each example, can you identify which name corresponds to a binary compound instead of a binary acid? That’s right! Hydrogen fluoride and hydrogen bromide are the binary compounds. When you add the prefix, ‘hydro,’ and change the ending, ‘ide’ to ‘ic,’ you’ve named a binary acid. In this table, you’ll find a list of common binary acids.
Binary acids are a class of acids defined by the bonding of a hydrogen atom to a nonmetal element. These acids can be strong or weak, depending on chemical factors, such as bond strength, dissociation constant and electronegativity. Binary acids are not the same as binary compounds, a difference determined by physical state.
While binary acids are aqueous, binary compounds are gases and liquids. When naming a binary acid, we use the prefix ‘hydro’ and suffix ‘ic.’ Examples of binary acids include hydrobromic acid (HBr), hydrochloric acid (HCl), hydrofluoric acid (HF), and hydroiodic acid (HI).