The table lists the solubility of two six-carbon compounds in liquid water at 25 °C
CHEMISTRY · Single correct · A Level · Chemistry · Carboxylic acids and derivatives · Carboxylic acids and derivatives
Problem
The table lists the solubility of two six-carbon compounds in liquid water at 25 °C.
Compound Solubility (g per 100 mL H2O)
Hexanoic acid 1.0
1-Hexanol 0.06
Which of the following best accounts for the considerably greater water solubility of hexanoic acid compared with 1-hexanol?
(a) 1-Hexanol molecules form an extensive hydrogen-bonded network with one another that water molecules cannot easily disrupt, so very little 1-hexanol dissolves.
(b) Because the carbonyl group makes hexanoic acid more polar than 1-hexanol, it experiences stronger dipole–dipole attractions to water and thus dissolves better.
(c) Hexanoic acid can ionize slightly to form RCOO− and H+, permitting strong ion–dipole as well as hydrogen-bond interactions with water.
(d) Hexanoic acid can form twice as many hydrogen bonds with water as 1-hexanol because it has two oxygen atoms, leading to much greater solubility.