Naming Alcohols - Online Tutor, Practice Problems & Exam Prep

Rules for Naming Alcohols Concept 1

Now, before we delve into naming alcohols, recall that alcohols possess a hydroxyl group. The hydroxyl group is the OH group, and it's connected to an sp³ hybridized carbon. Here, the set of rules for naming alcohols are similar to alkanes, plus a modifier ending. Now here, what exactly is a modifier? Well, the modifier is the change to the suffix or ending because of the presence of a functional group. As we go from functional group to functional group, we're going to have different types of modifiers. Now, here for alcohols, the modifier modifies the ending of the alkane name of e to ol. So instead of like pentane, we have pentanol. Here the naming convention is we have to give still the locations of our different substituents, remember those are our branch groups, the location of our parent in terms of our OH group, and then the modification to the ending. In this case, going from an e ending to ol. So keep this in mind when we're naming different types of alcohols.

Naming Alcohols Example 1

Here in this example question, it says, "Name the following alcohol compound." Alright. So, we're going to use the following steps in order to name this particular alcohol. Here, step 1 says that we have to find the longest carbon chain. That longest carbon chain represents our parent chain. And we're going to assign a name according to the prefixes and now modifier. Now, the parent chain should include the OH group, since we're talking about an alcohol, and have the greatest number of carbons. Now, if a tie exists between the longest chains, choose the chain with more substituents. This one is pretty straightforward. Our longest chain we can see is this portion right here, and we can see that the OH and the Cls act as our substituents. So this leads us into step 2, assign a name to all the substituents. Alright. So here our chlorines would be chloro. The alcohol itself is going to be a modifier, so we don't have to name it here. Next, we're going to say start numbering the chain from the end closest to the OH group. If a tie, number from the end closest to the next substituent. If still a tie, number in alphabetical order. Now, assign the numerical location to the carbon with the OH group. So here we've identified the two substituents in terms of chlorine, we've looked at the longest chain, we know that OH is going to be our functional group that's going to modify the end of the name. So here, I've already numbered the chain for us. We're numbering it from this end 1 because, going 1, 2, we get to our first substituent. If we had numbered it from the other end, it would take us 1, 2, 3 before we get to a substituent. That takes too long. Alright. So now, let's finally name this. We're going to say here that a 6 carbon chain is hexane, but remember the presence of the OH changes the ending from 'e' to 'ol,' so it becomes hexanol. We have to state on what carbon the OH is for the alcohol; it's on carbon 3, so this would be 3-hexanol. Remember, we use a dash to separate numbers from letters. Next, we said that these chlorines are chloro, there are two of them, so that would be dichloro. And finally, we have to state on what carbons those two chlorines are found. They're found on carbons number 2 and 4. So this would be 2,4-dichloro-3-hexanol. So "2,4-dichloro-3-hexanol" will be the name of this particular alcohol compound.

Provide the systematic name for the following alcohol.

• A. 1-methyl-1-hydroxycyclohexane
• B. 1-methylcyclohexanol
• C. 1-methyl-1-hydroxyhexane
• D. 1-methylhexanol

Provide the formal name for the following alcohol. 

• A. 3-isopropyl-4,5,6-trimethyloctanol
• B. 2-isopropyl-1,3,4,5-tetramethylheptanol
• C. 3-isopropyl-4,5,6-trimethyl-2-octanol
• D. 6-isopropyl-3,4,5-trimethyl-2-octanol

Which structure represents 2-bromo-2,3-dichloro-1-heptanol?

• A.
• B.
• C.
• D.

Name the following dialcohol.

• A. hexane-3,6-diol
• B. hexane-3,6-ol
• C. heptane-3,6-diol
• D. heptane-2,5-diol

Provide IUPAC name for the following trialcohol.

• A. 1,1-dibromohexane-1,3,5-triol
• B. 1,1-dibromopentane-1,2,4-triol
• C. 1,1-dibromopentane-2,4-diol
• D. 5,5-dibromopentane-2,4,5-triol

Alcohol Classification Concept 2

Alcohols can be classified based on how many carbon groups are attached to the OH-bearing carbon atom. So here we have classifications of primary, which is 1º, secondary, which is 2º, and tertiary which is 3º. If we take a look here at the first one, we have a carbon with our OH group. We'd say that the carbon with the OH group, let's say it's connected to just one carbon here. That would mean that this is a primary alcohol. Now, here let's put 2 carbons. So now that the carbon that bears the OH group is connected to 2 carbons, it's secondary. And then finally, we can say in this last image, the carbon possessing the OH group, it's directly connected to 3 carbons, meaning that it is a tertiary alcohol. So, remember, in our exploration to name different types of alcohols, you're going to come into contact with primary, secondary, tertiary alcohols, including also methyl alcohols, which don't belong to any of these categories. Right? So just keep this in mind when looking at different types of alcohols.

Alcohol Classification Example 2

Here it says that we need to classify the following alcohols. So let's look to see where is the carbon with the OH group. So here's the carbon with the OH group, and here's the carbon with the OH group. In the first image, that carbon possessing the OH group is connected to 2 other carbons which we don't see, here and here. Since it's connected directly to 2 carbons, it is a secondary alcohol. And then for this other one, this carbon with the OH group, it is directly connected to 1 carbon here. So here it's connected directly to one carbon, so this would represent a primary alcohol. The first compound is secondary, and the second one here is primary.

Label each alcohol as primary, secondary, or tertiary.

• A.
• B.
• C.
• D.