Final answer:
The net ionic equation is 3Ba²+ (aq) + 2PO³ ¯(aq) → Ba3(PO4)2 (s).
Step-by-step explanation:
The net ionic equation resulting from the mixture of BaBr2 and K3PO4 solutions is 3Ba²+ (aq) + 2PO³ ¯(aq) → Ba3(PO4)2 (s). This equation represents the balanced reaction between Ba²+ ions and PO4³- ions to form Ba3(PO4)2 solid. The spectator ions, K+ and Br-, are not included in the net ionic equation as they do not participate in the reaction.