Why do some solvents dissolve a solute wheras others dont?

Answer 1

A general rule is that "like dissolves like." there are exceptions but it holds true for many solvents. "Like" refers to polarity. For example, water is a polar molecule so it will dissolve other polar molecules.

Answer 2

Three main events take place when a solute dissolves in a solvent. Firstly, the lattice of cations and anions collapses, setting free the lattice ions into the solvent. Sondly, hydrogen bonds in the solvent are broken, Thirdly, the ions become hydrated by an interaction between the ions and the solvent dipoles.
Solvent molecules thus tend to become loosely bound to these ions. For a salt to dissolve, the energy required to collapse the lattice and break hydrogen bonds in the solution must be compensated for by the energy set free during the hydration process. The overall process is finely balanced. There are factors such as enthalpy and entropy.

For a solute to dissolve in a solvent, the particles which make up the solid crystal lattice must be driven apart. To remove the particles from the lattice (ions or molecules), energy must be supplied. In order to stay apart, and remain in solution, the attraction forces between the solute particles and the solvent molecules must be greater than the forces which tend to bind the ions or molecules together in the lattice. In case the force of attraction between the solute and the solvent is lesser than the respective binding force, then the solvent does not dissolve the solute.

In general, ions (which are charged) are attracted to the molecules of polar solvents, while non-polar molecules are attracted by the non-polar molecules of non-polar solvents.
"Like dissolves like". A polar substance is more likely to dissolve in a polar solvent and a non-polar substance is more likely to dissolve in a non-polar solvent.

Answer 3

It depends whether your solvent and solute is polar or nonpolar. The general rule of thumb is that "like dissolves like." Polar solutes dissolve in polar solvents and nonpolar solutes dissolve in nonpolar solvents.

For example, tablesalt is sodium chloride or NaCl. In water (H20), NaCl breaks down into its ions, Na+ and Cl-. This breaking down is what we witness as dissolving. This happens because the polar molecules of water surround the individual ions in the solution until they are covered in water molecules.

Answer 4

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