For each solute, identify the better solvent: water or hexane.
Water, H2O
Hexane, C6H14
Answer Bank
CO
1
CHÚNH
NH3
NO
B
The Correct Answer and Explanation is:
Let’s break this down by understanding the solubility principles and the nature of the solvents involved:
- Water (H₂O) is a polar solvent. This means it has a significant dipole moment, with a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. Water is very good at dissolving other polar substances and ionic compounds because of the hydrogen bonding and electrostatic interactions that occur between the solute and the solvent molecules.
- Hexane (C₆H₁₄), on the other hand, is a nonpolar solvent. It consists of long hydrocarbon chains, which interact primarily through London dispersion forces. Nonpolar solvents, like hexane, are generally better at dissolving other nonpolar substances because they can interact effectively with other molecules that lack significant polarity.
Now, let’s evaluate the solubility of the given solutes in water and hexane based on their polarity:
- CO (Carbon monoxide): Carbon monoxide is a small, polar molecule, and it will be more soluble in water. Its dipole moment allows it to interact with water molecules via hydrogen bonding and dipole-dipole interactions, making it more soluble in the polar solvent.
- NH₃ (Ammonia): Ammonia is a highly polar molecule with a lone pair of electrons on nitrogen, which can form hydrogen bonds with water. This makes water the better solvent for ammonia. Ammonia is very soluble in water due to the ability to form hydrogen bonds.
- NO (Nitric oxide): Nitric oxide is a polar molecule but is much less polar than ammonia or CO. It will dissolve better in water than in hexane, as the polar water molecules can still interact with the polar NO molecule. However, its solubility will not be as high as that of more highly polar molecules like ammonia.
Summary:
- CO: Water
- NH₃: Water
- NO: Water
Explanation:
The solubility of a solute in a given solvent depends primarily on the principle “like dissolves like.” Polar solutes tend to dissolve well in polar solvents (like water), and nonpolar solutes dissolve better in nonpolar solvents (like hexane). Since all three of the given solutes (CO, NH₃, and NO) are polar, they will all dissolve better in water, which is also polar.