What's the name of the following compound? H3C-H2C-H2C-SO3H

I would call it 1-propanesulfonic acid.

To determine the name of the compound H3C-H2C-H2C-SO3H, we need to identify the functional groups and follow the rules of organic nomenclature.

Step 1: Identify the longest carbon chain in the molecule.
In this case, the longest carbon chain contains three carbon atoms.

Step 2: Number the carbon atoms in the chain.
Start numbering from the end closest to the first group encountered (SO3H in this case), which is attached to the second carbon atom. This will give us the lowest possible number for the substituent.

Step 3: Identify and name any substituents or functional groups.
The molecule contains an SO3H group, which is called a sulfonic acid. It is attached to the second carbon atom in the chain.

Step 4: Assign a name to the compound by combining the names of the substituents and the parent carbon chain.
The parent carbon chain is propane (since it has three carbon atoms). The sulfonic acid group is named as a substituent, so we call it 2-sulfonic acid.

Therefore, the name of the compound H3C-H2C-H2C-SO3H is 2-propane sulfonic acid.