This is another one. You can see this one has one two three four different carbons. So This one is not propanoic acid. It's got full carbons and therefore it would be but and You can see the acid group on the end here. So the double bonded oxygen and then the Hydroxyl group. So oh and an H here which creates a C O O H Functional group and this functional group is characteristic of the acid. So that makes it butan noic acid This particular molecule also goes by the common name of butyric acid It has a particularly strong smell. It's almost mandatory if you're going to study organic chemistry that you will Encounter this particular molecule at some point and let me tell you you'll know when you do A lot of the acids have more common names. So for example If I break this molecule in half and just create this little one here. He's one that you're very familiar with As a lender would call it chaku the CH3 and the C double O H is our chaku It's two carbons with an acid functional functional group. So because it's two carbons with the acid functional group It's called ether noic acid now we have encountered it more commonly or we've named it more commonly Is acetic acid acetic acid is a correct name, but it's not the preferred OUPAC name the preferred OUPAC name is ether noic acid It's also the the key component in vinegar So this is a very important group of acids methanolic acid, which is this one is Also goes by the name of formic acid and it's an acid that's associated with And the substance that they release when you Know you die Each what the thing with this group is they're characterized by the fact that all of them have a fairly strong aroma and as we use these acids in some of our chemical reactions later on in this module you will encounter that particular Factor so again, you're just looking for the C double O H, which is your functional group and the total number of Carbons we have all together tells us about the night. So again in this case This would be methanolic acid as it's preferred OUPAC name