Final answer:
The chemical formula for liquid propanol is C3H8O, which is represented by option C) C3H8O. Propanol has a three carbon backbone like propane with a -OH group, and the empirical formula does not change with different isomers.
Step-by-step explanation:
The chemical formula for liquid propanol is C3H8O. When analyzing its structure, propanol has a backbone of three carbon (C) atoms similar to propane (C3H8) but with a hydroxy group (-OH) in place of one hydrogen atom. This structure composes propanol, an alcohol, which is reflected in the naming conventions where 'propane' serves as the base name and the suffix '-ol' is added because of the presence of the hydroxy group.
Propanol can exist in isomeric forms such as 1-propanol and 2-propanol (isopropyl alcohol, (CH3)2CHOH), but no matter the position of the hydroxy group, the empirical formula remains the same. Thus, the empirical formula for propanol would still be C3H8O as stated previously. Therefore, the correct answer to the student's question is option C) C3H8O.