Given the compounds CH_3OH (methanol) and CH_3CH_2CH_2CH_3 (butane), which would you expect to have the greater viscosity at room temperature?

• A. CH_3CH_2CH_2CH_3 (butane)
• B. CH_3OH (methanol)

Answer: (B)

Verified step by step guidance

1. Identify the molecular structures and intermolecular forces present in each compound: CH_3OH (methanol) contains an -OH group capable of hydrogen bonding, while CH_3CH_2CH_2CH_3 (butane) is a nonpolar hydrocarbon with only London dispersion forces.
2. Recall that viscosity is influenced by the strength of intermolecular forces; stronger intermolecular forces generally lead to higher viscosity because molecules resist flow more.
3. Analyze the types of intermolecular forces: methanol exhibits hydrogen bonding, which is significantly stronger than the London dispersion forces present in butane.
4. Consider molecular size and shape: although butane is larger, its nonpolar nature means weaker intermolecular attractions compared to methanol's hydrogen bonds.
5. Conclude that methanol's hydrogen bonding results in greater intermolecular attraction and thus higher viscosity at room temperature compared to butane.