In A Large Resealable Plastic Bag, Combine The Soda, Soy Sauce, Oil, Garlic Powder And Horseradish; Add Chicken. Seal The Bag And Turn To Coat. Refrigerate Overnight. Drain And Discard Marinade. Grill Chicken, Uncovered, Over Medium Heat For 6-7 Minutes On Each Side Or Until Juices Run Clear.