AP® Chemistry

Free Version

Upgrade subject to access all content


$NaCl$ with Water and Hexane


Just because you mix two things together does not necessarily mean that they will form a homogeneous mixture (a solution).

For example, if you add sodium chloride ($NaCl$) to a container that has both hexane and water, the $NaCl$ will dissolve into the water, but will not be found in the hexane $C_6H_{14}$.

Which of the following statements BEST explains these observations?


Polar water molecules form ion-dipole forces with the ions of $NaCl$. Hexane, being nonpolar, cannot form these ion-dipole interactions.


Nonpolar hexane molecules tend to repel the ions that make up $NaCl$.


Nonpolar hexane is less dense that water, so when the two are in the same container, any $NaCl$ that is added to the mixture sinks to the bottom of the container and cannot get into the hexane layer.


Nonpolar hexane molecules and water molecules repel one another.