What is the structural formula for propanol?

• A. CH3 CH2 CH2 OH
• B. CH3CH2CH2OH
• C. CH3CH2OH
• D. C3H7OH

Answer: (A)

Propanol is an alcohol with three carbon atoms in a row and a hydroxyl group attached to the end. The structural formula should show that connectivity clearly. CH3-CH2-CH2-OH does exactly that: a three-carbon chain with the OH on the terminal carbon, which is propan-1-ol. Writing it as CH3CH2CH2OH conveys the same structure, just without the hyphens, so it’s the same correct representation. CH3CH2OH refers to ethanol (two carbons), not propanol. C3H7OH gives the same composition but doesn’t show how the atoms are connected, so it isn’t a structural formula.