Final answer:
The state of KBr in the given reaction is aqueous (aq), meaning it is dissolved in water as K+ and Br- ions.
Step-by-step explanation:
In the chemical reaction given, KBr (aq) + AgNO3 (aq) → KNO3 (aq) + AgBr (s), the state of KBr is aquaeous (aq), which means that it is dissolved in water as ions. Compounds in aqueous solutions dissociate into their respective ions. In this case, KBr dissociates into K+ (aq) and Br- (aq) when it is in an aqueous solution.