Final answer:
The reaction KI(aq) + AgNO3(aq) → AgI(s) + KNO3(aq) is a double-replacement reaction, where two ionic compounds form a precipitate and another soluble compound.
Step-by-step explanation:
The reaction KI(aq) + AgNO3(aq) → AgI(s) + KNO3(aq) is a double-replacement reaction. In this type of reaction, the cations and anions of two ionic compounds exchange partners to form two new compounds. One of the products formed is silver iodide (AgI), which is an insoluble solid that precipitates out of the solution, and the other is potassium nitrate (KNO3), which remains in the aqueous phase.
Such reactions are also known as exchange reactions, and a classic example is when a precipitate, gas, or water is produced. This can be contrasted with single-replacement reactions, like Mg(s) + 2Ag+ (aq) + 2NO3- (aq) → Mg2+ (aq) + 2NO3- (aq) + Ag(s), where an element and a compound react to yield a different element and compound, and with decomposition reactions, where a single compound breaks down into two or more substances.