Solubility is a measure of the ability of a substance to dissolve in a solvent, such as water. Determining which of the following compounds is soluble in water is an important step in understanding the properties of the compound and its potential uses.
Types of Compounds
There are three main types of compounds that can be soluble in water: ionic compounds, polar covalent compounds, and non-polar covalent compounds. Ionic compounds are compounds that have a positive and negative charge, such as table salt (NaCl). Polar covalent compounds are compounds that have one end with a partial positive charge and the other end with a partial negative charge, such as acetic acid (CH3COOH). Nonpolar covalent compounds are compounds that are composed of two or more atoms that are held together by covalent bonds and do not have a charge, such as methane (CH4).Solubility of Compounds
Ionic Compounds
Ionic compounds are generally soluble in water, due to the electrostatic attraction between the positively-charged ions (cations) and the negatively-charged ions (anions). However, some ionic compounds are not soluble in water, such as silver chloride (AgCl).Polar Covalent Compounds
Polar covalent compounds are also generally soluble in water, due to the electrostatic attraction between the partially positively-charged end and the partially negatively-charged end. However, some polar covalent compounds are not soluble in water, such as hexane (C6H14).Nonpolar Covalent Compounds
Nonpolar covalent compounds are generally not soluble in water, due to the lack of electrostatic attraction. However, some nonpolar covalent compounds are soluble in water, such as ethanol (C2H5OH).Comparison
| Type of Compound | Generally Soluble in Water? |
|---|---|
| Ionic | Yes |
| Polar Covalent | Yes |
| Nonpolar Covalent | No |