When silver nitrate (AgNO₃) and iodine (I₂) are mixed together in an aqueous solution, a precipitation reaction occurs, forming a yellow precipitate of silver iodide (AgI).

Here's the balanced chemical equation:

2AgNO₃(aq) + I₂(aq) → 2AgI(s) + 2NO₃⁻(aq)

Explanation:

* Silver nitrate (AgNO₃) dissolves in water to form silver ions (Ag⁺) and nitrate ions (NO₃⁻).

* Iodine (I₂) dissolves slightly in water to form iodine ions (I⁻).

* When these solutions are mixed, silver ions (Ag⁺) and iodine ions (I⁻) react to form silver iodide (AgI), which is insoluble in water and precipitates out as a yellow solid.

* The nitrate ions (NO₃⁻) remain in solution as spectator ions and do not participate in the reaction.

Key observations:

* The formation of a yellow precipitate is a clear indication of this reaction.

* The reaction is exothermic, meaning it releases heat.

This reaction is used in analytical chemistry to determine the presence of iodine and in photography as a light-sensitive material.