Question

用英语解答

Answer 1

A1

a)

 (i) The functional group of alcohol molecules is hydroxyl which will form hydrogen bonds with the hydroxyls in water molecules when alcohol dissolving. By contrast, the haloalkanes don’t have the same property.

(ii) As shown in fig.

b) As shown in fig.

B2

 a) The two solvents are water andacetone. When X is dissolved in water, a clear interface between the water phase and the compound phase would be observed while in acetone, a homogeneous mixture would be generated.

  b) The “like dissolve like” principle would explain the results.

追问

why are most non-polar substances insoluble in polar solvents？

追答

For a substance to dissolve the cohesive energy of the bonds holding the solid or liquid solute together, and the energy cost of disrupting the solvent-to-solvent bonds must be overcome by the cohesive energy released by the formation of the solute-to-solvent bonds. Thus there are two energy "costs" (one solute/solute and one solvent/solvent) and two energy "gains" (two solute/solvent bonds). If these energies are approximately equal, which occurs when the solvent and solute molecules are structurally similar, then the substance will dissolve in the solvent.
Hence the saying: "Likes dissolve Likes.".

追问

thank you

追答

u r welcome ^ ^