In a large bowl mix the barbecue sauce with the soda, add the chicken, cover, and refrigerate for at least 2 hours.
Spray broiler pan with nonstick cooking spray, move rack to middle position, and preheat broiler.
Place broiler pan under heat for 5 minutes, using oven mitts, carefully remove and place chicken breasts, rib side down. Broil until thoroughly cooked about 25-30 minutes. Throw out remaining marinade.