Question

now, lets connect what you learned from examining isopropyl alcohol to your case.
earlier, you learned that certain ions are soluble in water. remember that the molecule youre looking for must be able to dissolve in water (and oil, but well get to that later). what type of structural feature should the molecule were looking for have?
which of the following characteristics of a particle may allow it to dissolve in water?
☐ it must have areas with a positive charge only
☐ it must have areas with a negative charge only
☐ it must have areas of both positive and negative charge such that they cancel each other out.
☐ it should have a polar region that concentrates electrons in a particular part of the molecule
☐ it could contain an area with a full charge such as an ion
☐ it must only contain areas of slight positive charge

Explanation:

Water is a polar molecule. Polar molecules have regions of partial positive and negative charges. For a particle to dissolve in water (a polar solvent), it should have similar polarity - related characteristics.

• A particle with only positive charge (option 1) or only negative charge (option 2) is too simplistic. Water interacts with both positive and negative aspects.
• If charges cancel out (option 3), the molecule would be non - polar and not dissolve well in water.
• A polar region (option 4) can interact with water's polar regions through dipole - dipole interactions.
• An ion (option 5) can interact with water's polar regions (positive ions with the negative end of water's dipole and negative ions with the positive end of water's dipole) through ion - dipole interactions.
• Only having slight positive charge (option 6) is not sufficient as water has both partial positive and negative regions.

Answer:

D. It should have a polar region that concentrates electrons in a particular part of the molecule; E. It could contain an area with a full charge such as an ion.