Which solvent, water or hexane (C6H14), would you choose to dissolve each of the following?1. NaCl2. HF3. Octane4. (NH4)2SO4

            Water for;

                            (a) NaCl

                            (b) HF

                            (c) (NH₄)₂SO₄

            Hexane for;

                             (a) Octane

Explanation:

                     In chemistry there is a Rue of Thumb, "Like Dissolves Like" according to which polar compounds will dissolve in polar solvents and non-polar compounds will dissolve in  non-polar solvents.

In given statement two solvents are given.

             (1) Water: Water is a polar compound. It has a polar bond and a bent shape, hence has a net dipole moment.

             (2) Hexane: Hexane is nonpolar because the electronegativity difference between the carbon atom and hydrogen atom is very less i.e. 0.4.

Therefore, polar solutes like NaCl (ionic), HF (highly polar) and (NH₄)₂SO₄ (ionic compound) will dissolve in water and Octane (C₈H₁₈ nonpolar) will dissolve in hexane respectively.