You should never give your dog baking soda on it's own through a spoon but adding some baking soda to some dog treats when baking them is okay and safe for your dog.
Just don't let your dog eat a large quantity of baking soda in a short amount of time and your dog will be okay.
Baking soda becomes poison to dogs if you give the baking soda to the dog in large quantities.
Dog treats that include baking soda are safe for your dog to eat in moderation.