Final answer:
If you need a substitute for baking soda, you can use a baking powder in a higher amount, as it is less potent. For baking powder, create a mix of cream of tartar and baking soda at a 2:1 ratio. These substitutes can change the taste and texture of the biscuits.
Step-by-step explanation:
When baking biscuits, should you find yourself without baking powder or baking soda, several substitutes can be used. Baking soda is sodium hydrogen carbonate, which reacts with acids to produce carbon dioxide. In baking powder, this acid is typically a solid acid like potassium hydrogen tartrate (cream of tartar). The carbon dioxide produced helps to leaven and add volume to your biscuits. If you're out of baking powder, you can use a mix of cream of tartar and baking soda. Use a ratio of 2:1, two parts cream of tartar to one part baking soda.
Additionally, in the case of baking soda, if you need one teaspoon, you can use four teaspoons of baking powder as a replacement since baking powder is weaker. However, it's important to remember that these replacements can affect the final flavor and texture of your biscuits.