Question

Drag the solute into the box that labels which solvent it will dissolve more easily within?

`" "" "" "color(white)(.)"CCl"_4" "" "" "" "" "" "" "" "" "" "" ""H"_2"O"`
`barul|stackrel(" ")(" "color(white)(stackrel(" ")("Place solute here"))" ")|" "" "" "" "barul|stackrel(" ")(" "color(white)(stackrel(" ")("Place solute here"))" ")|`

Sodium sulfide
Hexane
Iodine
Formaldehyde

Answer 1

The idea is that a solute that has intermolecular forces more similar to those in a solvent are more likely to mix well. Therefore:

• Ionic compounds dissolve well in water, which can hydrogen-bond. Hydrogen-bonding interactions are generally close in strength to ion-pair interactions, which are present in ionic compounds.

Hence, it is a "good trade of energy" for ionic compounds to dissolve in water.

Think of it like trading things with someone else. You want a good deal when you trade, so you don't want to just hand over something valuable for something totally worthless in return.

• Nonpolar compounds like hydrocarbons dissolve well in nonpolar solvents, for the same reasons as above; successful solvation is dependent on a "good trade of energy".

Here's a hint:

SOLUTES

• Sodium sulfide is ionic.
• Hexane is nonpolar.
• Iodine is nonpolar.
• Formaldehyde is polar.

SOLVENTS

• Water hydrogen-bonds.
• Carbon tetrachloride is nonpolar.

Your final result should be an even distribution of answers; two on the left and two on the right.