Methylbutane is a common name, and there's no single molecular formula associated with it. It refers to a group of isomers, which are molecules with the same chemical formula but different structural arrangements.

Here's the breakdown:

* Isomers of Methylbutane:

* 2-Methylbutane (Isobutane): CH₃CH(CH₃)CH₃

* 3-Methylbutane (Isopentane): CH₃CH₂CH(CH₃)CH₃

Therefore, you need to specify which isomer you are referring to when asking for the molecular formula.

Both isomers have the same molecular formula: C₅H₁₂