Question

Determine the best solvent to dissolve the given solute. Explain your answer by discussion intermolecular forces.

A) Which solvent is best to dissolve LiCl and why?

water (H₂O) or hexane (C₆H₁₄)

B) Which solvent is best to dissolve CH₃OH and why?

ammonia (NH₃) or carbon tetrachloride (CCl₄)

C) Which solvent is best to dissolve C₆H₆ and why?

water (H₂O) or carbon tetrachloride (CCl₄₎

Answer 1

A) Water is the best solvent to dissolve solid LiCl. It dissolves because the Li⁺ ions are attracted to the oxygen atom of water and the Cl^- ions are attracted to the hydrogen atom of water.

Polar solvent such as water dissolves polar solutes as well as ionic solutes such as LiCl. "Like solvent dissolves like". This refers to the nature of the intermolecular forces existing between the solute and the solvent.. Polar solutes and ionic solutes dissolve in polar solvents because the strengths of the intermolecular forces in solution are about the same as in pure solute and pure solvent. They are different in non-polar solvent like hexane and the energetics are so unfavorable, polar solutes do not dissolve in nonpolar solvents, and vice versa.

B) Ammonia is the best solvent to dissolve methanol. Methanol dissolves in ammonia as it is is polar because N is more electronegative than H

"Like solvent dissolves like". This refers to the nature of the intermolecular forces existing between the solute and the solvent.. Polar solutes and ionic solutes dissolve in polar solvents because the strengths of the intermolecular forces in solution are about the same as in pure solute and pure solvent.

C) CCl₄ is the best solvent to dissolve benzene. Non-polar solvent such as CCl₄ dissolves nonpolar solutes such as hexane.

"Like solvent dissolves like". This refers to the nature of the intermolecular forces existing between the solute and the solvent.. Non-polar solutes dissolve in non-polar solvents because the strengths of the intermolecular forces in solution are about the same as in pure solute and pure solvent.