Chemistry Homologous series


Why does the solubility in water of carbon molecules(in all homologous series )decrease with increasing carbon atoms ?

1 個解答

  • 7 年前

    For a molecule to dissolve in water, it is usually polar or capable to form hydrogen bonds.

    However, addition of the NON-POLAR carbon chains will make these molecules less polar(compared to their size) and form less extensively H-bonds.

    For a solute to dissolve in the solvent, the energy released from solute-solvent interaction should compensate energy absorbed from breaking solute-solute interactions and solvent-solvent interactions.

    With the decrease in polarity and ability to form H-bonds, these molecules form WEAKER interactions with water molecules. The energy released from solute-solvent interaction is hence lower and can't compensate the energy absorbed. These molecules then can't dissolve in water well.

    資料來源: ME