Naming Acids - Online Tutor, Practice Problems & Exam Prep

Acids are covalent compounds that typically begin with a hydrogen ion (H⁺), also known as a hydronium ion. These compounds are composed only of nonmetals. An example of an exception to this rule is acetic acid, which can be written with the hydrogen ion at the end, as in:

CH₃COOH Binary acids are a subset of acids that bond hydrogen ions to nonmetal anions, excluding oxygen. To name binary acids, the prefix 'hydro-' is used, followed by the base name of the nonmetal and ending with 'ic acid.' For example,

HCl becomes hydrochloric acid.

Oxy acids, on the other hand, are covalent compounds that contain hydrogen ions bonded to a polyatomic ion with oxygen. The naming of oxy acids is based on the ending of the polyatomic ion: if it ends in '-ate,' the acid name ends in '-ic acid' (e.g., nitrate to nitric acid), and if it ends in '-ite,' it changes to '-ous acid' (e.g., nitrite to nitrous acid). Understanding the structure and naming conventions of acids is crucial for recognizing and categorizing different types of chemical compounds.

Naming Acids

Before we start naming assets, let's first talk about what exactly is an acid. Now, an acid is usually a covalent compound beginning with a hydrogen ion. So hydrogen ion in this case is H+ and another name for this hydrogen ion is called the hydronium ion.

Now going back to covana, what exactly is meant by covalent compound? Well a covalent compound is a compound that contains only non metals bonded together. Now if you don't remember who the nonmetals are, make sure you go back and take a look at my videos on the periodic table and the classifications of the elements that lie within it.

If we take a look here some common types of acids, all of them are covalent because all of them possess non metal together. And since they're all covalent, we also see next that they all begin with hydrogen. That tells us that they all represent acids. So HCl, HNO2, H2SO4. We see that some of them are pretty simple like HCl and some of them are pretty complicated like H3PO4.

We'll talk about the different types of acids later on and the rules associated with naming them. Now remember we said that they usually begin with the hydrogen ion usually does not mean always and with chemistry you're going to see that exceptions do OU here and there. A good exception to this is acetic acid.

Now acetic acid can be drawn two different ways. The 1st way goes along with the definition we have, it starts with the hydrogen and it's covalent because it only has non metals. But another way to write acetic acid is CH3COOH. In this case, the hydrogen ion is actually written in the back. OK, so this is an exception to our definition, where this is still an acid, but it doesn't begin with the hydrogen ion.

Now that we know the basic structure of an acid, let's move on to some videos and let's tackle the different types of acids that exist and the ways of naming them.

Naming Acids

So here, let's take a look at binary assets. Now binary acids, since they're acid, they are also represented as covalent compounds and they're going to contain the H⁺ ion, which is our hydrogen ion. But here they're going to be bonded to a non metal anion that is not oxygen. So binary acids are covalent compounds, usually beginning with hydrogen, that contain no oxygen.

Here, how do we form them? Well, we know that they possess the H ion and let's think of a non metal that can be connected to in the anion form, which means they have a negative charge. So let's say we're dealing with iodine. Iodine is in Group 7A so its charge is -1. So here we have plus one from the hydrogen, -1 from the iodine. If you've seen our videos on writing ionic compounds, we alley the same principles here. Remember, if the numbers in the charges are the same, they simply cancel out and you combine together your elements. So here this would be HI. HI would represent a typical binary acid.

All right, so here rules for naming these binary assets. Well, step one is the prefix they're they're going to use. The prefix they use is hydro and that basically represents the H ion. And then we're going to say Step 2, use the base name of the nonmetal. Now here's the thing, remember the base name is usually the beginning part of the beginning name of the nonmetal that is being used and it's unchanged except when we use sulfur or phosphorus.

So it in their acid forms. For sulfur we actually use the entire name. We don't use the base name, we use the entire name for sulfur. And for phosphorus, we don't just use its base name, we use a little bit more. The base name of phosphorus is phosphor, but in acid form we actually use OR as well. So again, the nonmetal part of the acid that is not the H, we use its base name except for sulfur and phosphorus, we use a little bit more than just their base names.

Then finally, to end the name of the binary acid, we use ick acid for the end of the name. So we apply these principles and we'll be able to name any type of binary app.

Naming Acids Example 1

So for this example question, it says write the formula for each of the following compounds. We have hydro iota acid, hydro sealenic acid, and hydrofluoric acid. All right, So we're going to say that hydro, we know that represents the H ion involved, so we have H⁺ for all of these. Since they're all binary assets, we know they all end with ick acid. What we look at is the base name. The base name tells us the nonmetal involved. So iode means we're dealing with iodine. It's in Group 7A, so it's one sillin means we're dealing with Selenium. It's in Group 6A, so it's 2^- or -2 and then floor means we're dealing with fluorine, which is in Group 7A, so it is -1.

Now for the first one for a. Remember, when the numbers and the charges are the same, they simply cancel out and you combine your elements together. So hydroiodic acid is just HI. And then also for C +1 -1, the numbers are the same, so you just combine them together. So hydrofluoric acid is HF. For B hydrosalenic acid. We have here different numbers in the charges. Remember when the numbers are different they crisscross. So one from here comes here 2 from here comes here O. That means hydrocellenic acid is H₂Se.

If you don't quite remember these rules, make sure you go back and take a look at our videos talking about writing ionic compounds. It's the same kind of principles behind this. We look at the ions and charges. If the numbers are the same, they simply cancel out. If the numbers are different and they crisscross, using this helped us to determine each one of these three binary acids. Now that we've done this example, move on to the next video where we take a look at a practice problem.

Give the systematic name for the following compound:H₂S

• A. sulfuric acid
• B. hydrosulfuric acid
• C. sulfic acid
• D. hydrosulfic acid
• E. hyposulfuric acid

Give the systematic name for the following compound:HCN

• A. cyanate acid
• B. cyanous acid
• C. hydrocyanous acid
• D. cyanic acid
• E. hydrocyanic acid

Naming Acids

When it comes to oxy acids, Oxy acids represent our second type of acid. Now we're going to say they represent covalent compounds because they're acids. They contain hydrogen ion as well, but now they're bonded to a polyatomic ion containing oxygen, and it's pretty clear why that is because the name is Oxy, highlighting the fact that we have oxygen present now.

So how could we form an Oxy acid? Well, here we have our H ion, so H1, and let's just think of a polyatomic ion that possesses oxygen. Here we could have NO3-. NO3- is our nitrate ion. And remember, when the numbers in the charges are the same, they just simply cancel out and you combine together your elements. So HNO3 would represent an Oxy acid.

It is covalent because it possesses only nonmetals, it has your hydrogen ion at the beginning of the compound structure. And altogether we have our oxy acid. Now that we know how they're formed and what they represent. Click on to the next video and let's go over the rules for naming them.

Naming Acids

When it comes to naming oxy acids, it's first important to remember your polyatomic ions. Now, if you don't remember your polyatomic ions or you haven't watched my videos on them, I suggest you pause this video and go back and take a look at those videos first. Then come back and we can tackle naming oxy acids together.

All right, so for those of you who are ready, let's go. We're going to say here rules for naming oxy acids. Rule one. If the polyatomic ion ends with -ate, then change the ending when it's in its acid form to -ic acid. Here we have a memory tool that'll help us. So here we're going to say I⁸ and acid and it was icky. Now don't go biting into acids or eating them in any way, but just remember that -ate goes with icky.

OK, so in its polyatomic ion form, it's -ate, but in its acid form we change the ending to -ic acid. So here we have H⁺ with NO₃^-. Remember NO₃^- is your nitrate ion. When I combine them together to give me HNO₃, that is our oxy acid form. Here the -ate ending changes to -ic acid, so nitrate becomes nitric acid.

But remember we also have polyatomic ions that end with -ite. What do we do in those situations? Well, we're going to say if the polyatomic ion ends with -ite then in its acid form we'll change the ending to -ous acid. And again, we have a great memory tool, so I only bite into delicious, into things that are delicious. So this will help us remember if we have a polyatomic ion that ends with -ite in its acid form it becomes -ous ending -ous acid.

So here we have H⁺ with NO₂^-. NO₂^- is our nitrite ion. When it combines with H⁺ we get HNO₂ which is our oxy acid form. The -ite ending changes to -ous acid, so nitrite becomes nitrous acid. So again, unless you know your polyatomic ions, it gets pretty tricky in terms of naming the oxy acid form. So first make sure you've mastered the polyatomic ions and then we can start naming oxy acids.

Now that we've seen the rules for this, let's continue on with some questions and test what we've learned.

Naming Acids Example 2

In this example question, it says write the formula for each of the following compounds. All right. So for A we have H2CO3. All right. So think about what is making up this oxyacid. Well we know that this is H+ and we know here this CO3 is all together. The two that comes here originated from the CO3 because here this is carbonate ion. Remember the ending is 8. Remember I ate an acid and it was icky. So that means that eight will become ick acid. So that means that this represents carbonic acid. So H2CO3 is carbonic acid.

Next, H3PO3. What makes it up? We know we have H+ here and we know that PO3 here, polyatomic ion wise it was 3 minus. We also know based on what we've seen in the polyatomic ion videos that this would be called phosphate. Phosphate ending ends with eight. So remember, if it ends with eight, we're going to say here that I bite into things that are delicious, right? So I becomes osacid. Also remember that phosphorus we use more than just the base. Base name. We also include or and then it would be OS acid. So this is phosphorus acid.

Finally, we have H2SO4, which is composed of H+ and SO4 which is a polyatomic ion that is 2 minus. It's one of our common types of Tetra oxides. All right, so this is called sulfate. It ends with eight. So that means that our acid form would be ick acid. Just like phosphorus sulfur uses more than just the base name, so we actually use the whole name sulfur. And remember 8 becomes ick acid, so this is sulfuric acid as the name for our oxy acid.

So again, you have to remember your polyatomic ions because they go hand in hand with learning and recognizing the Oxy acid forms that exist. Now that we've done this example, let's continue onward with more practice on naming Oxy acids.

Write the formula for the following compound:Hypobromous acid  

• A. HBrO
• B. H₂BrO
• C. HBrO₂
• D. HBrO₃
• E. H₂BrO₄

Write the formula for the following compound:Cyanic acid

• A. HCNO
• B. HOCN
• C. H₂OCN
• D. HO₂CN
• E. HCN

Here’s what students ask on this topic:

What are the rules for naming acids?

In chemistry, acids are named based on the presence or absence of oxygen in the molecule. Here are the general rules for naming acids:

1. Binary Acids: These are acids that consist of hydrogen and one other nonmetal element. When naming a binary acid, you start with the prefix "hydro-", then add the stem of the nonmetal element's name, and finally add the suffix "-ic" followed by the word "acid". For example, HCl (hydrogen chloride) is named hydrochloric acid.
2. Oxyacids: These acids contain hydrogen, oxygen, and another element (the central atom). The naming depends on the polyatomic ion (the ion with multiple atoms) that the acid is derived from:

• If the polyatomic ion ends in "-ate", change the ending to "-ic" and add "acid". For example, HNO 3 (nitric acid) is derived from the nitrate ion NO 3 - .
• If the polyatomic ion ends in "-ite", change the ending to "-ous" and add "acid". For example, HNO 2 (nitrous acid) is derived from the nitrite ion NO 2 - .

Remember, you don't use the "hydro-" prefix for oxyacids, and the "ic" or "ous" suffix.

Which rule should be followed when naming binary acids?

When naming binary acids, which are acids that consist of hydrogen and one other nonmetallic element, there is a specific nomenclature rule to follow:

1. Start with the prefix "hydro-".
2. Add the root of the name of the nonmetal element.
3. End with the suffix "-ic".
4. Follow with the word "acid".

For example, if you have an acid with hydrogen and chlorine, you would name it hydrochloric acid. Here, "hydro-" indicates the presence of hydrogen, "chlor-" is the root for chlorine, and "-ic" is the suffix used for binary acids. Finally, the term "acid" is added to indicate that the compound is indeed an acid. So, H 2 S in aqueous solution is called hydrochloric acid, while H 2 S would be named hydrosulfuric acid. Remember, this rule is only for binary acids in their aqueous form; the naming convention changes for molecular compounds and oxyacids.