Select correct statement about alcohol solubility in water.

• A. 2-hexanol is more soluble than 2-pentanol.
• B. Methanol is soluble while butanol is slightly soluble.
• C. Butane and 1-butanol have equal solubility.
• D. 1-octanol is slightly soluble.

Answer: (B)

Verified step by step guidance

1. Understand that alcohol solubility in water depends on the balance between the hydrophilic (–OH) group and the hydrophobic hydrocarbon chain. The –OH group can form hydrogen bonds with water, increasing solubility, while longer hydrocarbon chains decrease solubility due to their nonpolar nature.
2. Compare alcohols by their carbon chain length: shorter chain alcohols like methanol and ethanol are highly soluble in water because the –OH group dominates their interactions, whereas longer chain alcohols like 1-octanol have reduced solubility due to the larger hydrophobic portion.
3. Recognize that isomers with similar chain lengths but different branching (e.g., 2-hexanol vs. 2-pentanol) may have slightly different solubilities, but the general trend is that increasing chain length decreases solubility.
4. Note that alkanes like butane are nonpolar and do not form hydrogen bonds with water, so their solubility is negligible compared to alcohols like 1-butanol, which can hydrogen bond and thus are more soluble.
5. Conclude that statements about methanol being soluble and butanol being slightly soluble, and 1-octanol being slightly soluble, align with the chemical principles of solubility based on molecular structure and hydrogen bonding capability.