Ethanol (CAS 64-17-5): C2H5OH, bp 78.4°C. Miscible with water. Hydrogen bonding via -OH gives it a high bp vs similar-mass alkanes. Solvent, antiseptic, fuel additive. Key feedstock for ester synthesis.
Benzene (CAS 71-43-2): The parent aromatic hydrocarbon, C6H6. All six C-C bonds are equal (139 pm) due to delocalized π-electrons. Hückel rule: 4n+2 = 6 π electrons. A known carcinogen — replaced by toluene/xylene in most lab applications. Discovered by Faraday in 1825.
Acetic acid (CAS 64-19-7): A simple carboxylic acid, CH3COOH. Pure acetic acid is called glacial acetic acid (mp 16.6°C). pKa 4.76 — a weak acid that gives vinegar its sour taste and pungent smell. Industrially produced via carbonylation of methanol (Monsanto/BP Cativa process).