A material that settles out of a reaction is termed a

• A. Colloid
• B. Precipitate
• C. Sediment
• D. Suspension

Answer: (A)

When a reaction in solution produces a solid that leaves the dissolved phase, that solid is called a precipitate. This happens when the product is insoluble under the reaction conditions, so it forms as a solid that can separate from the liquid. Over time, those solid particles may settle to the bottom, forming a sediment. Colloids are mixtures with very small particles that stay dispersed and don’t settle quickly; suspensions have larger particles that can settle but aren’t defined by being the solid formed in a reaction. So the solid formed in a reaction that separates from the solution is the precipitate.