The three substances that cause a double displacement reaction to occur are: (i) Ionized compounds. These are usually water. (ii) A gas that bubbles out a solution. (iii) A precipitate.
In double displacement reaction is where two new compounds are formed when two parts of two compounds switch places. For example; when sodium chloride combines with silver nitrate, the two new compounds formed are Sodium nitrate and silver chloride reason being sodium and silver switched places.
