There are two possible isomers for a hydrocarbon with the molecular formula C4H10. These are:

* Butane: This is a straight-chain alkane with four carbon atoms.

* Isobutane (or 2-methylpropane): This is a branched alkane with three carbon atoms in a chain and one methyl group attached to the second carbon atom.

Here's a simple visual representation:

Butane: CH3-CH2-CH2-CH3

Isobutane: CH3-CH(CH3)-CH3