Concept:The solubility of organic compounds in water is a battle between the hydrophilic (water-loving) polar head and the hydrophobic (water-fearing) non-polar hydrocarbon tail.
Solution:- The carboxyl group (\( -\text{COOH} \)) is hydrophilic and promotes solubility via hydrogen bonding.
- As the molecular mass increases (by adding more \( -\text{CH}_2 - \) units to the alkyl chain), the hydrophobic non-polar tail grows larger and more dominant.
- This bulky hydrocarbon tail disrupts the water's hydrogen bond network, rendering the overall molecule increasingly insoluble.
Why other options are incorrect:Decreasing molecular mass actually
increases solubility (e.g., acetic acid is infinitely soluble). The other options describe concentrations, not inherent molecular solubility traits.
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