Here in this example question it says provided below is a structure of an alkane. Identify names of alkyl groups present in red. All right, so if we take a look here, this is our chain, and these alkyl groups are the branches coming off of that chain.
If we take a look at the first one, so it's branching off. This branch group here has one 2-3 carbons that are not part of this main chain. 3 carbons means there's one of two possibilities, either propyl or isopropyl. It would be propyl if the connection to the main chain happened at one of the end carbons, but instead it's happening at the middle carbon, meaning that this alkyl group is isopropyl.
Next we have this carbon branching off of the main chain. It is just a single carbon, so we know it's an alkyl group, so it's YL. And one carbon has the prefix of meth, so this would be methyl.
Next we have this chain branching off of the main chain, so this is 1 2-3 carbons long. Those 3 carbons, the bonds at one of the ends, so this would be propyl.
And then finally we have this one branching off, which is made U of 1-2 carbons. We know the ending is yl 2 carbons, its prefix would be F, so those two carbons would be ethyl.
So our four alkyl groups in this alkane are isopropyl, methyl, propyl, and ethyl. So those would be our final answers.