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The alkanes that share the same molecular formula of C4H10 are butane and isobutane. These two compounds are structural isomers, meaning they have the same molecular formula but different arrangements of atoms. Butane has a straight-chain structure, while isobutane (also known as methylpropane) has a branched structure.

Both compounds exhibit the characteristics of alkanes, such as being saturated hydrocarbons with single bonds and showing similar chemical properties due to having the same number of carbon and hydrogen atoms. This is what allows them to be classified under the same molecular formula despite their differences in structure and properties.

The other combinations listed do not share the molecular formula C4H10, as they represent different alkanes with distinct molecular formulas. For example, ethane and butane have different molecular formulas (C2H6 and C4H10 respectively), and propane and pentane also do not share the same molecular formula as they correspond to C3H8 and C5H12. Methane and ethane differ in molecular formulas as well, being C1H4 and C2H6 respectively.