Final answer:
Isomers are molecules with the same molecular formula but different arrangements of atoms. N-butane does not have isomeric forms in the context given, and molecules CH3CH2COOH and C3H6O2 can be structural isomers, whereas methane, ethane, and propane do not have isomeric forms due to their simple structures.
Step-by-step explanation:
Understanding Isomers
To determine which molecule is not an isomer of the others, one must first understand the concept of isomers. Isomers are molecules that have the same molecular formula but differ in the arrangement of their atoms. There are several types of isomers, including structural isomers and stereoisomers. Structural isomers have different covalent arrangements of atoms, while stereoisomers have the same covalent arrangements but differ in spatial orientations, being further categorized as enantiomers or diastereomers.
Based on the information given, and considering the details about n-butane, structural isomers would exhibit different branching of their carbon chains. N-butane, for example, does not have isomeric forms within the context of the provided structures, as they all represent an unbranched chain of four carbon atoms. The concept of enantiomers involves molecules that are nonsuperimposable mirror images, with a requirement that a molecule must have at least four different atoms or groups connected to a central carbon atom to be considered enantiomers.
In the case of molecules with formulas CH3CH2COOH and C3H6O2, they could indeed be structural isomers of each other, which negates the false statement option that claims they couldn't. Finally, compounds such as methane, ethane, and propane do not have isomeric forms because there aren't multiple ways to arrange their atoms to satisfy the four bonds to carbon criteria, unlike C4H10.