What’s the difference? It’s that C=O group again. Ether has C-O-C group, while ester has a C=O-O-C group. Let’s look at the second pair – ether and ester. What’s the difference? It’s that C=O group. Alcohol has a hydroxyl (OH) group while carboxylic acid has a carboxyl (COOH) group. First pair – alcohol and carboxylic acid. Once you get these two columns down, the middle column compounds are similar to the third column, with the difference of missing a carbonyl (C=O) group. Reason being when carbonyl (C=O) group meets hydroxyl (OH) group, they merge to become carboxyl (COOH) group (see below). Carboxylic acid consists of a carbo xyl (COOH) group, not carbo nyl (C=O) group. The carbonyl compounds in this group are aldehyde, ketone, ester and amide. The third column (purple box) consists of compounds containing carbonyl (C=O) and carboxyl (COOH) group. Remove one hydrogen and replace with a halogen (fluorine, chlorine, bromine and iodine), and you get alkyl halide (see the image below). Meaning, it was made from a hydrocarbon, specifically alkane.

The fifth member, alkyl halide, is actually a hydrocarbon derivative. The first 4 members are alkane, alkene, alkyne and arene. The first column (pink column) consists of hydrocarbons compounds which are made of only carbons and hydrogens. See the image on top of this post? I’ve strategically placed the 13 groups in a manner where we can easily group them and recall when needed. Thirteen?!!! Yea, thirteen! Don’t worry, it’ll be easier to remember them if you group them in a manner that makes sense. Do you dread having to remember all the functional groups? If you are in an introductory chemistry course, chances are high that you need to know these 13 functional groups.

Ether functional group