Question

Just because you mix two things together does not necessarily mean 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 $C_6{H}_{14}$.
Which of the following statement BEST explains these observations?

• A. Polar water molecules form ion-dipole forces with the ions of $NaCl$. Hexane, being nonpolar, cannot form these ion-dipole interactions.
• B. Nonpolar hexane molecules tend to repel the ions that make up $NaCl$.
• C. 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.
• D. Nonpolar hexane molecules and water molecules repel one another.

Answer 1

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

Like dissolve like is a principle behind homogeneous mixing (i,e formation of solution). For example NaCl is ionic (polar) so it get dissolve in $H_{2}O$ (polar). but not in haxane (non-polar ) due to ion- dipole interaction between NaCl and $H_{2}O$.