At university, the tutor encountered the world of organic chemistry – as many of you have or will.  Although it comes up rarely in high school tutoring, a basis is beneficial before you face it at post-secondary level.

If you haven’t read my earlier organic chemistry articles here and here, you may wish to do so. Continuing from them, we look today at naming alcohols.

Example 1: Name this molecule.

Step 1: Count the carbons in the chain. In this case, we have 9.

Step 2: Refer to the table in this post, which gives the name of the chain based on its number of carbons.

Step 3: Counting from the end of the chain closest to the OH, decide which carbon the OH is on. In this case, OH is on the fourth carbon.

Step 4: The name starts with the number of the carbon that has the OH, followed by a hyphen, then the chain name from Step 1. At the end of the chain, replace -ane with -ol, which means the molecule is an alcohol.

In our example, the OH is on the fourth carbon. The chain has nine carbons, suggesting nonane. Therefore, our molecule is 4-nonanol.

OH means alcohol in the context of organic chemistry. Not all molecules with OH are alcohols; nevertheless, OH is called “the alcohol group”.

Here are a couple more alcohols:

A final example reminds the student to count from the end of the chain that is nearest the alcohol group:

Many people might mistake the alcohol above for 5-hexanol. However, since the OH is nearer the bottom, you count up from there.

There are many more complicated alcohols – and of course other organic molecules – to name. Look for them in future posts:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.