If you’ve made biscuits, scones or other baked goods that did not rise properly, one reason might be that the baking soda and/or baking powder used was old and not activating. To test baking soda, mix 1/4 tsp. with 2 tsp. vinegar. If the baking soda is still good, it will bubble immediately. To test baking powder, mix 1 tsp. with 1/2 cup hot water. If it's still good, this mixture will bubble immediately.