Is their a substitute for Baking soda?? I'm doing a vegan cake...and just noticed that I have no baking soda left?

Please help

Baking Soda (Sodium Bicarbonate)
(Rule of Thumb: 1/4 teaspoon for every 1 cup of flour)
1/2 teaspoon 2 teaspoons double-acting baking powder (must replace the acidic liquid in recipe with non-acidic liquid)
1/2 teaspoon potassium bicarbonate


here's a site with substitutions to help you in the future: http://www.joyofbaking.com/IngredientSubstitution.html

you could give baking powder a try - are you using vinegar to help with the levening? ; according to a q&a on the food network site:

Baking powder is similar to baking soda, though it's about a quarter as strong, and it's mixed together with exactly the right proportion of acid in order for it to activate.

http://www.foodnetwork.com/food/ck_culinary_qa/article/0,,FOOD_9796_4349208,00.html

Thank you guys with all the help!