An insoluble solid that forms as a result of a double-displacement reaction is called a precipitate.

Here's a breakdown:

* Double-displacement reaction: A reaction where two reactants exchange ions, leading to the formation of two new products.

* Insoluble: Not able to dissolve in a particular solvent (usually water).

* Precipitate: The insoluble solid that forms and separates from the solution during a reaction.

Example:

When you mix solutions of silver nitrate (AgNO₃) and sodium chloride (NaCl), a precipitate of silver chloride (AgCl) forms:

AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

* AgCl is the precipitate, which is a white solid that is insoluble in water.

Knowing the solubility rules of ionic compounds can help you predict whether a precipitate will form in a double-displacement reaction.