1. A precipitation reaction occurs when two aqueous solutions react to form an insoluble solid. 2. The solid formed is called a precipitate. 3. All precipitation reactions involve acids and bases only. Which of the above statements are correct?

Statements 1 and 2 are correct because a precipitation reaction is defined by the formation of an insoluble solid when two aqueous solutions are mixed. Precipitation reactions typically involve ionic salts reacting through double displacement, whereas reactions involving only acids and bases are called neutralisation reactions. These reactions occur when the attraction between certain ions in a solution is stronger than their attraction to water molecules, causing them to bond and 'fall out' of the solution.