Question

Explain the solubility of ionic compounds and covalent compounds in water.

Answer 1

Ionic compounds dissolve in water due to attraction between the ionic solid and water molecules. Covalent compounds have lower solubility and do not conduct electricity. The solubility of ionic compounds depends on the nature of the compound.

Step-by-step explanation:

Ionic compounds dissolve in polar solvents, especially water. This occurs when the positive cation from the ionic solid is attracted to the negative end of the water molecule (oxygen) and the negative anion of the ionic solid is attracted to the positive end of the water molecule (hydrogen). Water is considered the universal solvent since it can dissolve both ionic and polar solutes, as well as some nonpolar solutes (in very limited amounts). The solubility of a solid in water increases with an increase in temperature.

Many covalent compounds do not dissolve in water, whereas most ionic compounds dissolve well in water. Unlike ionic compounds, covalent compounds do not have freely moving electrons, so they cannot conduct electricity. The individual molecules of covalent compounds are more easily separated than the ions in a crystal, so most covalent compounds have relatively low boiling points. This explains why many of them are liquids or gases at room temperature.

The solubility of ionic compounds in water depends on the nature of the compound. For example, lead(II)iodide (PbI₂) and silver chloride (AgCl) are insoluble in water because the solubility of PbI2 is 0.0016 mol/L of the solution and the solubility of AgCl is about 1.3 x 105 mol/L of solution. Potassium iodide (KI) and Pb(NO3)2 are soluble in water. When aqueous solutions of KI and Pb(NO3)2 are mixed, the concentration of PbI₂ in the mixture goes above its solubility limits, and it precipitates out.

Answer 2

So,

Ionic compounds tend to be soluble or dissolve in water because water is a polar compound that can exert enough force to overcome the ionic bond and cause the ions to go into solution. In general covalent compounds are less soluble in water. The tendency of compounds to dissociate or ionize in water tells a great deal about the way in which bonds hold the compound itself together. Covalent compounds aren't usually very soluble in water.

When ionic compounds dissolve in water they go through a process called dissociation, splitting into the ions that make them up. However, when you place covalent compounds in water, they typically do not dissolve but form a layer on top of the water.