Question

Pipette 3 drops of oil into a test tube of water and shake. Describe what takes place and why?

- Would it be the oil settles at the top of the water, because the oil is less dense, and its a non-polar substance, so it doesn't mix with a polar substance (water).

Add 1 scoop of NaCl into a test tube of water and shake. Describe what takes place and why.

This one I am confused on because apparently NaCl is nonpolar? But I thought nonpolar can only dissolve in nonpolar? So how does NaCl dissolve in water?

Answer 1

I agree with the oil/water mix.
For NaCl and H2O, who says NaCl is non-polar? It may not be the most polar compound in the world but it's in the top 90% anyway. The electronegativity for Na is about 0.9 and that for Cl is about 3.0 which makes a difference of about 2.1 and that's well over the 50% mark. Don't forget when describing the solubility of NaCl to include that the H2O molecules attract the Na^+ and Cl^- and tear apart the crystalline lattice.