Evaluating statements on alcohol synthesis and properties Steps:

• Review standard methods: Steam hydration of alkenes yields ethanol (primary alcohol).
• Check fermentation: Glucose yields ethanol via yeast.
• Assess renewability: Bioethanol from biomass is renewable; synthetic alcohols are not.
• Analyze isomers: Alcohols with formula C_nH_{2n+2}O have one isomer for n=1 (methanol) or n=2 (ethanol), multiple for higher n. Not enough information on structures of Alcohols 1–4 to fully evaluate. Why D is correct:
• Alcohol 4 must be methanol or ethanol, which have only one structural isomer per molecular formula (C_nH_{2n+2}O for n=1 or 2). Why the others are wrong:
• A: Steam addition to alkenes specifically produces ethanol; Alcohol 1 likely differs (e.g., branched or secondary).
• B: Glucose fermentation yields ethanol; Alcohol 2 likely not ethanol (e.g., methanol or propanol).
• C: Only bioethanol is typically a renewable energy source; Alcohol 3 likely synthetic (e.g., methanol from CO/H2). Final answer: D