Final answer:
Propane, C3H8, has two sets of equivalent hydrogens: one set of six equivalent hydrogens in the methyl groups and one set of two equivalent hydrogens bonded to the central carbon. These are differentiated by their chemical environments relative to the carbon atoms they are attached to.
Step-by-step explanation:
In propane, C3H8, there are two sets of equivalent hydrogens. The molecule has a backbone of three carbon atoms, with hydrogen atoms bonded to these carbons. On the ends of the propane molecule are two methyl groups (CH3), each with three hydrogen atoms bonded to a carbon, which is itself bonded to only one other carbon. These six hydrogens are equivalent, since they are in the same chemical environment. The central carbon, however, is bonded to two other carbons, and the hydrogen atoms attached to this central carbon are thus in a different environment. There are two of these hydrogen atoms, making them the second type of equivalent hydrogens in propane. Therefore, propane has one set of six equivalent hydrogens (the methyl group hydrogens) and one set of two equivalent hydrogens (the central methylene hydrogens).