Final answer:
In a precipitation reaction, two ionic compounds that are dissolved in water form a new compound that does not dissolve and precipitates out as a solid. Solubility rules can be used to predict which compounds will precipitate.
Step-by-step explanation:
In a precipitation reaction, two ionic compounds that are dissolved in water form a new compound that does not dissolve and precipitates out as a solid. To determine which compounds will precipitate, we can use solubility rules. These rules give us general guidelines about which compounds are soluble and which are insoluble.
For example, if we mix solutions of silver nitrate (AgNO3) and sodium chloride (NaCl), the solubility rules tell us that silver chloride (AgCl) is insoluble. Therefore, a precipitation reaction occurs and AgCl precipitates out of the solution as a solid.
Other examples of compounds that commonly precipitate in precipitation reactions include calcium carbonate (CaCO3) and iron oxide (Fe2O3).