In a typical precipitation reaction, what is the state of the insoluble product?

• A. (aq)
• B. (g)
• C. (s)
• D. (l)

Answer: (C)

When ions in solution combine to form a compound that cannot dissolve, that new substance appears as a solid called a precipitate. Because it doesn’t dissolve in the solution, it settles out or forms a visible solid, so its state is solid (s) in equations. It isn’t aqueous, since it isn’t dissolved; it isn’t a gas, since it doesn’t escape as bubbles; and it isn’t a liquid, because it stays as a solid material.