Adding KBr (potassium bromide) and AgNO3 (silver nitrate) to a solution of water will produce a solid precipitate of the oxidant AgBrO3 (silver bromate).
The water contains 'spectator atoms' not involved in the production of the silver bromate solid, but produced from the ions generated by the two compounds' dissolving in water.
The silver bromate should appear as an insoluble white powder. If you are preparing silver bromate, please take care as it is toxic. Silver bromate has few practical uses, beyond lab experiments demonstrating the disassociation of ions in a chemical reaction involving bromide and silver.
For more details on how potassium bromide reacts with water, check out this YouTube film:
