Alright. So here we have an example problem that's asking which functional group listed down below over here is not present in this molecule over here. And so notice that the very first functional group listed is carboxyl. And recall that the carboxyl has the box in it which we know is going to store 2 other functional groups, the carbonyl group and the hydroxyl group. And so notice over here we have a carbon double bonded to an oxygen and we also have a hydroxyl group branching off.
And so together when we see this format like this we refer to it as a carboxyl group. So the carboxyl group is present here and we can go ahead and cross it off and label it as we see right here. Let's label this as carboxyl. Then moving on, what you'll also notice is that we have a OH group extending off of a carbon. And so the OH, recall, is going to be the hydroxyl group because it has the oxy in it for the oxygen and the hydro for the hydrogen.
And so, this here is going to be a hydroxyl group. And so because a hydroxyl group is here, we can go ahead and cross off option c as well. And then recall that amino groups are going to have a nitrogen atom in them. And so notice that the nitrogen atom is right here, and this here represents the amino group. And so the only one that is not present here is going to be the sulfhydryl group, which recall has a sulfur atom and a hydrogen atom.
But there are no sulfur atoms at all throughout here, so this is going to be the one that is not present in the molecule. So we can go ahead and indicate that b here is the correct answer for this example, and that concludes this example, so I'll see you all in our next video.